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class="vector-toc-link" href="#Theories_of_Montalembert_and_Carnot"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Theories of Montalembert and Carnot</span> </div> </a> <ul id="toc-Theories_of_Montalembert_and_Carnot-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Prussian_System" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Prussian_System"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Prussian System</span> </div> </a> <ul id="toc-Prussian_System-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Lessons_of_the_Crimean_War" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Lessons_of_the_Crimean_War"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Lessons of the Crimean War</span> </div> </a> <ul id="toc-Lessons_of_the_Crimean_War-sublist" 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class="vector-toc-link" href="#Sources"> <div class="vector-toc-text"> <span class="vector-toc-numb">8.1</span> <span>Sources</span> </div> </a> <ul id="toc-Sources-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet 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href="https://es.wikipedia.org/wiki/Fuerte_poligonal" title="Fuerte poligonal – Spanish" lang="es" hreflang="es" data-title="Fuerte poligonal" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Fortificazione_a_base_poligonale" title="Fortificazione a base poligonale – Italian" lang="it" hreflang="it" data-title="Fortificazione a base poligonale" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Polygonaal_stelsel" title="Polygonaal stelsel – Dutch" lang="nl" hreflang="nl" data-title="Polygonaal stelsel" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li> 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searchaux" style="display:none">Type of fortification</div><figure class="mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Fort_I_Grundriss.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/1/11/Fort_I_Grundriss.jpg/300px-Fort_I_Grundriss.jpg" decoding="async" width="300" height="207" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/11/Fort_I_Grundriss.jpg/450px-Fort_I_Grundriss.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/11/Fort_I_Grundriss.jpg/600px-Fort_I_Grundriss.jpg 2x" data-file-width="2064" data-file-height="1425" /></a><figcaption>An 1868 plan of Fort I of the ring fortress at <a href="/wiki/Magdeburg" title="Magdeburg">Magdeburg</a>, typical of mid-19th century polygonal forts</figcaption></figure> <p>A <b>polygonal fort</b> is a type of <a href="/wiki/Fortification" title="Fortification">fortification</a> originating in France in the late 18th century and fully developed in Germany in the first half of the 19th century. Unlike earlier forts, polygonal forts had no <a href="/wiki/Bastion" title="Bastion">bastions</a>, which had proved to be vulnerable. As part of ring fortresses, polygonal forts were generally arranged in a ring around the place they were intended to protect, so that each fort could support its neighbours. The concept of the polygonal fort proved to be adaptable to improvements in the artillery which might be used against them, and they continued to be built and rebuilt well into the 20th century. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Bastion_system_deficiencies">Bastion system deficiencies</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Polygonal_fort&action=edit&section=1" title="Edit section: Bastion system deficiencies"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Process_of_attack.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/e/e1/Process_of_attack.png/220px-Process_of_attack.png" decoding="async" width="220" height="203" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/e/e1/Process_of_attack.png/330px-Process_of_attack.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/e/e1/Process_of_attack.png/440px-Process_of_attack.png 2x" data-file-width="1098" data-file-height="1014" /></a><figcaption>A diagram showing Vauban's method of approaching an enemy fortification using saps and parallels</figcaption></figure> <p>The <a href="/wiki/Bastion_fort" title="Bastion fort">bastion system</a> of fortification had dominated military thinking since its introduction in 16th century Italy, until the first decades of the 19th century. The French engineer <a href="/wiki/S%C3%A9bastien_Le_Prestre_de_Vauban" class="mw-redirect" title="Sébastien Le Prestre de Vauban">Sébastien Le Prestre de Vauban</a> also devised an effective method to defeat them. Before Vauban, besiegers had driven a <a href="/wiki/Sapping" title="Sapping">sap</a> towards the fort until they reached the <a href="/wiki/Glacis" title="Glacis">glacis</a>, where artillery could be positioned to fire directly on the scarp wall to make a breach. Vauban used saps to create three successive lines of entrenchments surrounding the fort, known as "parallels". The first two parallels reduced the vulnerability of the sapping work to a <a href="https://en.wiktionary.org/wiki/sally#Etymology_2" class="extiw" title="wikt:sally">sally</a> by the defenders, while the third parallel allowed the besiegers to launch their attack from any point along its circumference. The final refinement devised by Vauban was first used at the <a href="/wiki/Siege_of_Ath_(1697)" title="Siege of Ath (1697)">Siege of Ath</a> in 1697, when he placed his artillery in the third parallel at a point close to the bastions, from where they could ricochet their shot along the inside of the <a href="/wiki/Parapet" title="Parapet">parapet</a>, dismounting the enemy guns and killing the defenders.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> </p><p>Other European engineers quickly adopted the three-parallel Vauban system, which became the standard method and would prove to be almost infallible.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> Vauban designed three systems of fortification, each having a more elaborate system of <a href="/wiki/Outwork" title="Outwork">outworks</a>, which were intended to prevent the besiegers from enfilading the bastions. During the next century, other engineers tried and failed to perfect the bastion system to nullify the Vauban type of attack.<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> During the 18th century, it was found that the continuous <a href="/wiki/Enceinte" title="Enceinte">enceinte</a>, or main defensive enclosure of a bastion fortress, could not be made large enough to accommodate the enormous field armies which were increasingly being employed in Europe; neither could the defences be constructed far enough away from the fortress town to protect the inhabitants from bombardment by the besiegers, the range of whose guns was steadily increasing as better manufactured weapons were introduced.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Theories_of_Montalembert_and_Carnot">Theories of Montalembert and Carnot</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Polygonal_fort&action=edit&section=2" title="Edit section: Theories of Montalembert and Carnot"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size mw-halign-left" typeof="mw:File/Thumb"><a href="/wiki/File:FortQuerqueville.JPG" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f0/FortQuerqueville.JPG/220px-FortQuerqueville.JPG" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f0/FortQuerqueville.JPG/330px-FortQuerqueville.JPG 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f0/FortQuerqueville.JPG/440px-FortQuerqueville.JPG 2x" data-file-width="2592" data-file-height="1944" /></a><figcaption>Fort de Querqueville, one of the casemated coastal forts at <a href="/wiki/Cherbourg" title="Cherbourg">Cherbourg</a>, which was based on Montalembert's system</figcaption></figure> <p><a href="/wiki/Marc_Ren%C3%A9,_marquis_de_Montalembert" title="Marc René, marquis de Montalembert">Marc René, marquis de Montalembert</a> (1714–1800) envisaged a system to prevent an opponent from establishing their parallel entrenchments by an overwhelming artillery barrage from a large number of guns, which were to be protected from return fire. The elements of his system were the replacement of bastions with <a href="/wiki/Tenaille" title="Tenaille">tenailles</a>, resulting in a defensive line with a zigzag plan, allowing for the maximum number of guns to be brought to bear and the provision of gun towers or <a href="/wiki/Redoubt" title="Redoubt">redoubts</a> (small forts), forward of the main line, each mounting a powerful artillery battery. All the guns were to be mounted in multi-storey masonry <a href="/wiki/Casemate" title="Casemate">casemates</a>, vaulted chambers built into the <a href="/wiki/Rampart_(fortification)" title="Rampart (fortification)">ramparts</a> of the forts. Defence of the ditches was to be by <a href="/wiki/Caponier" title="Caponier">caponiers</a>, covered galleries projecting into the ditch with numerous <a href="/wiki/Loophole_(firearm)" title="Loophole (firearm)">loopholes</a> for small arms, compensating for the loss of the bastions with their flanking fire.<sup id="cite_ref-:0_6-0" class="reference"><a href="#cite_note-:0-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> Montalembert argued that the three elements, would provide long-range offensive fire from the casemated main curtain, <a href="/wiki/Defence_in_depth" title="Defence in depth">defence in depth</a> from the detached forts or towers and close-in defence from the caponiers.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> Montalembert described his theories in an eleven-volume work called <span title="French-language text"><i lang="fr">La Fortification Perpendiculaire</i></span>, which was published in Paris between 1776 and 1778.<sup id="cite_ref-:0_6-1" class="reference"><a href="#cite_note-:0-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> He summarised the benefits of his system thus; "...all is exposed to the fire of the besieged, which is everywhere superior to that of the besieger, and the latter cannot advance a step without being hit from all sides".<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> </p><p>A full realisation of Montalembert's ambitious plans for a great inland fortress was never attempted. Almost immediately after publication, unofficial translations into German were being made of Montalembert's work and were being circulated amongst the officers of the <a href="/wiki/Prussian_Army" title="Prussian Army">Prussian Army</a>. In 1780, <a href="/wiki/Gerhard_von_Scharnhorst" title="Gerhard von Scharnhorst">Gerhard von Scharnhorst</a>, a <a href="/wiki/Hanover" title="Hanover">Hanoverian</a> officer who went on to reform the Prussian Army, wrote that "All foreign experts in military and engineering affairs hail Montalembert's work as the most intelligent and distinguished achievement in fortification over the last hundred years. Things are very different in France". The conservative French military establishment was wedded to the principles laid down by Vauban and improvements made by his later followers, <a href="/wiki/Louis_de_Cormontaigne" title="Louis de Cormontaigne">Louis de Cormontaigne</a> and <a href="/wiki/Charles_Louis_de_Fourcroy" class="mw-redirect" title="Charles Louis de Fourcroy">Charles Louis de Fourcroy</a>. What little political influence the aristocratic Montalembert had during the <i><a href="/wiki/Ancien_R%C3%A9gime" class="mw-redirect" title="Ancien Régime">Ancien Régime</a></i> was lost following the <a href="/wiki/French_Revolution" title="French Revolution">French Revolution</a> in 1792.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> </p> <figure class="mw-default-size mw-halign-left" typeof="mw:File/Thumb"><a href="/wiki/File:Fort_Tign%C3%A9_map.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/8/88/Fort_Tign%C3%A9_map.png/220px-Fort_Tign%C3%A9_map.png" decoding="async" width="220" height="108" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/8/88/Fort_Tign%C3%A9_map.png/330px-Fort_Tign%C3%A9_map.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/8/88/Fort_Tign%C3%A9_map.png/440px-Fort_Tign%C3%A9_map.png 2x" data-file-width="1068" data-file-height="524" /></a><figcaption>A simplified plan of <a href="/wiki/Fort_Tign%C3%A9" title="Fort Tigné">Fort Tigné</a>, Malta, regarded as being the first true polygonal fort. The gun emplacements marked "8" are later additions.</figcaption></figure> <p>Despite the conservatism of the French engineer corps, two French engineers experimented on a modest scale with Montalembert's ideas for detached forts. <a href="/wiki/Jean_Le_Michaud_d%27Ar%C3%A7on" title="Jean Le Michaud d'Arçon">Jean Le Michaud d'Arçon</a>, ironically one of Montalembert's detractors, designed and built a number of <a href="/wiki/Lunette_(fortification)" title="Lunette (fortification)">lunettes</a> (an outwork resembling a detached bastion) which were in accord with Montalembert's concepts. These lunettes were constructed at <a href="/wiki/Mont-Dauphin" title="Mont-Dauphin">Mont-Dauphin</a>, <a href="/wiki/Besan%C3%A7on" title="Besançon">Besançon</a>, <a href="/wiki/Perpignan" title="Perpignan">Perpignan</a> and other border fortresses, commencing in 1791 shortly before the Revolution. In the same year, <a href="/wiki/Antoine_%C3%89tienne_de_Tousard" title="Antoine Étienne de Tousard">Antoine Étienne de Tousard</a> took up a position on <a href="/wiki/Malta" title="Malta">Malta</a> as an engineer to the <a href="/wiki/Knights_Hospitaller" title="Knights Hospitaller">Order of Saint John</a> and was instructed to design a small fort to command the entrance to <a href="/wiki/Marsamxett_Harbour" title="Marsamxett Harbour">Marsamxett Harbour</a> called <a href="/wiki/Fort_Tign%C3%A9" title="Fort Tigné">Fort Tigné</a>. Exactly how Tousard became acquainted with d'Arcon's lunette design is unknown, but the resemblance is too close to be coincidental. It was, like d'Arcon's works, <a href="/wiki/Quadrilateral" title="Quadrilateral">quadrilateral</a> in plan, divided by a traverse with a circular tower keep in the rear and the surrounding ditch was protected by <a href="/wiki/Counterscarp#Counterscarp_gallery" title="Counterscarp">counterscarp galleries</a>. Fort Tigné, however, was a fully defensible and self-contained fort, larger and more sophisticated than d'Arcon's outworks,<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> and is regarded as being the first true polygonal fort.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> </p> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Castle_Williams_2007_jeh.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/4/47/Castle_Williams_2007_jeh.jpg/220px-Castle_Williams_2007_jeh.jpg" decoding="async" width="220" height="231" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/47/Castle_Williams_2007_jeh.jpg/330px-Castle_Williams_2007_jeh.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/47/Castle_Williams_2007_jeh.jpg/440px-Castle_Williams_2007_jeh.jpg 2x" data-file-width="1145" data-file-height="1200" /></a><figcaption><a href="/wiki/Castle_Williams" title="Castle Williams">Castle Williams</a> in <a href="/wiki/New_York_Harbor" title="New York Harbor">New York Harbor</a>, constructed from 1807 according to Montalembert's system</figcaption></figure> <p>Montalembert's work was also allowed to take concrete form during his lifetime in the field of <a href="/wiki/Coastal_defence_and_fortification" title="Coastal defence and fortification">coastal fortification</a>. In 1778, he was commissioned to build a fort on the <a href="/wiki/%C3%8Ele-d%27Aix" title="Île-d'Aix">Île-d'Aix</a>, defending the port of <a href="/wiki/Rochefort,_Charente-Maritime" title="Rochefort, Charente-Maritime">Rochefort, Charente-Maritime</a>. The outbreak of the <a href="/wiki/Anglo-French_War_(1778%E2%80%931783)" title="Anglo-French War (1778–1783)">Anglo-French War</a> forced him hastily to build his casemated fort from wood but he was able to prove that his well-designed casemates were capable of operating without choking the gunners with smoke, one of the principal objections of his detractors.<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> The defences of the new naval base at <a href="/wiki/Cherbourg" title="Cherbourg">Cherbourg</a> were later constructed according to his system.<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> After seeing Montalembert's coastal forts, American engineer <a href="/wiki/Jonathan_Williams_(engineer)" title="Jonathan Williams (engineer)">Jonathan Williams</a> acquired a translation of his book and took it to the United States, where it inspired the <a href="/wiki/Seacoast_defense_in_the_United_States#Second_System" title="Seacoast defense in the United States">Second</a> and <a href="/wiki/Seacoast_defense_in_the_United_States" title="Seacoast defense in the United States">Third Systems</a> of coastal fortification; the first fully developed example being <a href="/wiki/Castle_Williams" title="Castle Williams">Castle Williams</a> in <a href="/wiki/New_York_Harbor" title="New York Harbor">New York Harbor</a> which was started in 1807.<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p><p><a href="/wiki/Lazare_Carnot" title="Lazare Carnot">Lazare Carnot</a> was an able French engineer officer, whose support for Montalembert had impeded his military career immediately after the Revolution. Taking up politics, he was made <a href="/wiki/Minister_of_the_Armed_Forces_(France)#Consulat_and_First_French_Empire" title="Minister of the Armed Forces (France)">Minister of War</a> in 1800 and retired from public life two years later. In 1809, <a href="/wiki/Napoleon_I" class="mw-redirect" title="Napoleon I">Napoleon I</a> asked him to write a handbook for the commanders of fortresses, which was published in the following year under the title <span title="French-language text"><i lang="fr">De la défense des places fortes</i></span>.<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> While broadly supporting Montalembert and rejecting the bastion system, Carnot proposed that an attacker's preparations should be disrupted by massed infantry sorties, supported by a hail of high-angle fire from <a href="/wiki/Mortar_(weapon)" title="Mortar (weapon)">mortars</a> and <a href="/wiki/Howitzer" title="Howitzer">howitzers</a>. Some of Carnot's innovations, such as the <a href="/wiki/Carnot_wall" title="Carnot wall">Carnot wall</a>, a loopholed wall at the foot of the <a href="/wiki/Counterscarp" title="Counterscarp">scarp face</a> of the rampart, to shelter defending infantry, were used in many later fortifications but remained controversial.<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Prussian_System">Prussian System</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Polygonal_fort&action=edit&section=3" title="Edit section: Prussian System"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Early_Forts_at_Cologne.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/0/02/Early_Forts_at_Cologne.png/220px-Early_Forts_at_Cologne.png" decoding="async" width="220" height="140" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/0/02/Early_Forts_at_Cologne.png/330px-Early_Forts_at_Cologne.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/0/02/Early_Forts_at_Cologne.png/440px-Early_Forts_at_Cologne.png 2x" data-file-width="779" data-file-height="496" /></a><figcaption>Early types of Prussian polygonal forts built at <a href="/wiki/Cologne" title="Cologne">Cologne</a> in 1817 and 1825</figcaption></figure> <p>After the final fall of Napoleon I in 1815, the <a href="/wiki/Congress_of_Vienna" title="Congress of Vienna">Congress of Vienna</a> founded the <a href="/wiki/German_Confederation" title="German Confederation">German Confederation</a>, an alliance of the numerous German states, dominated by the <a href="/wiki/Kingdom_of_Prussia" title="Kingdom of Prussia">Kingdom of Prussia</a> and the <a href="/wiki/Austrian_Empire" title="Austrian Empire">Austrian Empire</a>. Their priority was to establish a defensive system with the <a href="/wiki/Fortresses_of_the_German_Confederation" title="Fortresses of the German Confederation">Fortresses of the German Confederation</a> against France in the west and Russia in the east.<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> The Prussians started in the west by refortifying the fortress cities of <a href="/wiki/Koblenz" title="Koblenz">Koblenz</a> and <a href="/wiki/Cologne" title="Cologne">Cologne</a> (<a href="/wiki/German_language" title="German language">German</a>: <i lang="de">Köln</i>), both important crossing points on the <a href="/wiki/River_Rhine" class="mw-redirect" title="River Rhine">River Rhine</a>, under the direction of <a href="/wiki/Ernst_Ludwig_von_Aster" title="Ernst Ludwig von Aster">Ernst Ludwig von Aster</a> and assisted by <a href="/wiki/Gustav_von_Rauch" title="Gustav von Rauch">Gustav von Rauch</a>, both supporters of the Montalembert system.<sup id="cite_ref-19" class="reference"><a href="#cite_note-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> Clearly influenced by Montalembert and Carnot, the novel feature of these new works was that they were encircled by forts, each several hundred metres out from the original enceinte, carefully sited so as to make best use of the terrain and to be capable of mutual support with the neighbouring forts. The new fortifications established the principle of the <b>ring fortress</b> or <b>girdle fortress</b>.<sup id="cite_ref-20" class="reference"><a href="#cite_note-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> </p> <figure class="mw-default-size mw-halign-left" typeof="mw:File/Thumb"><a href="/wiki/File:K%C3%B6ln-Neustadt-S%C3%BCd_Fort_I_v_S%C3%BCden.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/5/52/K%C3%B6ln-Neustadt-S%C3%BCd_Fort_I_v_S%C3%BCden.jpg/220px-K%C3%B6ln-Neustadt-S%C3%BCd_Fort_I_v_S%C3%BCden.jpg" decoding="async" width="220" height="146" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/52/K%C3%B6ln-Neustadt-S%C3%BCd_Fort_I_v_S%C3%BCden.jpg/330px-K%C3%B6ln-Neustadt-S%C3%BCd_Fort_I_v_S%C3%BCden.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/52/K%C3%B6ln-Neustadt-S%C3%BCd_Fort_I_v_S%C3%BCden.jpg/440px-K%C3%B6ln-Neustadt-S%C3%BCd_Fort_I_v_S%C3%BCden.jpg 2x" data-file-width="5073" data-file-height="3366" /></a><figcaption>Fort I of the Cologne ring fortress at Neustadt-Süd, showing the gate in the gorge wall, protected by the reduit on the left</figcaption></figure> <p>The detached forts were polygons of four or five sides in plan, with the front faces of the rampart angled at 95°. The rear or gorge of the fort was closed with a masonry wall, sufficient to repel a surprise infantry attack but easily demolished by the defenders' artillery should the fort be captured by the attackers. In the centre of the gorge wall was a <a href="/wiki/Reduit" title="Reduit">reduit</a> or <a href="/wiki/Keep" title="Keep">keep</a>, provided with casemates for guns which could fire over the rampart or along the flanks to support the next forts in the chain.<sup id="cite_ref-21" class="reference"><a href="#cite_note-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> The original bastioned enceintes of these fortresses were initially retained or even rebuilt so as to prevent an attacker from infiltrating between the outlying forts and taking the fortress by a <i><a href="/wiki/Coup_de_main" title="Coup de main">coup de main</a></i>. It was later thought by some engineers that a simple entrenchment would suffice or that no inner defence was necessary; the issue remained a debating point for some decades.<sup id="cite_ref-22" class="reference"><a href="#cite_note-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> In any case, few European cities undergoing the rapid expansion caused by the <a href="/wiki/Industrial_Revolution" title="Industrial Revolution">Industrial Revolution</a> would willingly accept the restriction to their growth caused by a continuous line of ramparts.<sup id="cite_ref-23" class="reference"><a href="#cite_note-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup> Aster insisted that his new technique was "not to be regarded... as a particular system" but this type of ring fortress became known as the Prussian System. Austrian engineers adopted a similar approach although differing in some details; the Prussian System and the Austrian System were together known as the German System.<sup id="cite_ref-24" class="reference"><a href="#cite_note-24"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Lessons_of_the_Crimean_War">Lessons of the Crimean War</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Polygonal_fort&action=edit&section=4" title="Edit section: Lessons of the Crimean War"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The Crimean War (October 1853 to February 1856) was fought by the <a href="/wiki/Russian_Empire" title="Russian Empire">Russian Empire</a> and an alliance of the <a href="/wiki/Ottoman_Empire" title="Ottoman Empire">Ottoman Empire</a>, France, Britain and <a href="/wiki/Kingdom_of_Sardinia" title="Kingdom of Sardinia">Sardinia</a>. Russian fortifications, which included some modern advances, were tested against the latest British and French artillery. At <a href="/wiki/Sevastopol" title="Sevastopol">Sevastopol</a>, the focus of the allied effort, the Russians had planned a modern fortress but little work had been done and earthworks were rapidly constructed instead. The largest and most complex earthwork, the <a href="/wiki/Battle_of_the_Great_Redan" title="Battle of the Great Redan">Great Redan</a>, was found to be largely resistant to British bombardments and difficult to carry by assault. Only one stone casemated work, the <a href="/wiki/Battle_of_Malakoff" title="Battle of Malakoff">Malakoff Tower</a>, had been completed at the time of the allied landing and proved impervious to bombardment but was finally carried by French infantry in a <i><a href="/wiki/Coup_de_main" title="Coup de main">coup de main</a></i>.<sup id="cite_ref-25" class="reference"><a href="#cite_note-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup> In the <a href="/wiki/Battle_of_Kinburn_(1855)" title="Battle of Kinburn (1855)">Battle of Kinburn (1855)</a>, an Anglo-French fleet undertook a bombardment of the Russian fortress which guarded the mouth of the <a href="/wiki/Dnieper_River" class="mw-redirect" title="Dnieper River">Dnieper River</a>. The most successful weapon there was the <a href="/wiki/Paixhans_gun" title="Paixhans gun">Paixhans gun</a> which was mounted on <a href="/wiki/D%C3%A9vastation-class_ironclad_floating_battery" title="Dévastation-class ironclad floating battery">ironclad floating batteries</a>. These guns were the first to be able to fire explosive shells on a low trajectory and were able to devastate the open ramparts of the forts, causing their surrender within four hours. British attempts to subdue the casemated Russian forts at <a href="/wiki/Kronstadt" title="Kronstadt">Kronstadt</a> and other fortifications in the <a href="/wiki/Baltic_Sea" title="Baltic Sea">Baltic Sea</a> using conventional naval guns were far less successful.<sup id="cite_ref-26" class="reference"><a href="#cite_note-26"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Impact_of_rifled_artillery">Impact of rifled artillery</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Polygonal_fort&action=edit&section=5" title="Edit section: Impact of rifled artillery"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Fort_Nelson,_Portsdown_Hill,_look_from_south,_5-7-2018.png" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/3/37/Fort_Nelson%2C_Portsdown_Hill%2C_look_from_south%2C_5-7-2018.png/220px-Fort_Nelson%2C_Portsdown_Hill%2C_look_from_south%2C_5-7-2018.png" decoding="async" width="220" height="133" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/37/Fort_Nelson%2C_Portsdown_Hill%2C_look_from_south%2C_5-7-2018.png/330px-Fort_Nelson%2C_Portsdown_Hill%2C_look_from_south%2C_5-7-2018.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/3/37/Fort_Nelson%2C_Portsdown_Hill%2C_look_from_south%2C_5-7-2018.png/440px-Fort_Nelson%2C_Portsdown_Hill%2C_look_from_south%2C_5-7-2018.png 2x" data-file-width="2007" data-file-height="1215" /></a><figcaption><a href="/wiki/Fort_Nelson,_Hampshire" title="Fort Nelson, Hampshire">Fort Nelson</a> at <a href="/wiki/Portsmouth" title="Portsmouth">Portsmouth</a>, one of the <a href="/wiki/Palmerston_Fort" class="mw-redirect" title="Palmerston Fort">Palmerston Forts</a> built in the United Kingdom in the 1860s</figcaption></figure> <p>The first <a href="/wiki/Rifled_breech_loader" title="Rifled breech loader">rifled artillery</a> designs were developed independently during the 1840s and 1850s by several engineers in Europe. These weapons offered greatly increased range, accuracy and penetrating power over smooth-bore guns then in use.<sup id="cite_ref-27" class="reference"><a href="#cite_note-27"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> The first effective use of rifled guns was during the <a href="/wiki/Second_Italian_War_of_Independence" title="Second Italian War of Independence">Second Italian War of Independence</a> in 1859, when the French used them against the Austrians. The Austrians quickly realised that the outlying forts of their ring fortresses were now too close to prevent an enemy from bombarding a besieged town and at <a href="/wiki/Verona" title="Verona">Verona</a>, they added a second circle of forts, about 1 mi (1.6 km) forward of the existing ring.<sup id="cite_ref-28" class="reference"><a href="#cite_note-28"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup> </p><p>The British were apprehensive about a French invasion and in 1859 appointed the <a href="/wiki/Royal_Commission_on_the_Defence_of_the_United_Kingdom" title="Royal Commission on the Defence of the United Kingdom">Royal Commission on the Defence of the United Kingdom</a> to fortify the <a href="/wiki/Naval_dockyard" class="mw-redirect" title="Naval dockyard">naval dockyards</a> of southern England. The experts on the commission, led by Sir <a href="/wiki/William_Jervois" title="William Jervois">William Jervois</a>, interviewed Sir <a href="/wiki/William_Armstrong,_1st_Baron_Armstrong" title="William Armstrong, 1st Baron Armstrong">William Armstrong</a>, a major developer and manufacturer of rifled artillery and were able to incorporate his advice into their designs.<sup id="cite_ref-29" class="reference"><a href="#cite_note-29"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup> The ring forts at <a href="/wiki/Palmerston_Forts,_Plymouth" class="mw-redirect" title="Palmerston Forts, Plymouth">Plymouth</a> and <a href="/wiki/Palmerston_Forts,_Portsmouth" class="mw-redirect" title="Palmerston Forts, Portsmouth">Portsmouth</a> were set further out than the Prussian designs they were based on and the casemates of coastal batteries were protected by composite armoured shields, tested to be resistant to the latest heavy projectiles.<sup id="cite_ref-30" class="reference"><a href="#cite_note-30"><span class="cite-bracket">[</span>30<span class="cite-bracket">]</span></a></sup> </p> <figure class="mw-default-size mw-halign-left" typeof="mw:File/Thumb"><a href="/wiki/File:Le_foss%C3%A9_de_gorge_du_fort_d%27Uxegney.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/c1/Le_foss%C3%A9_de_gorge_du_fort_d%27Uxegney.jpg/220px-Le_foss%C3%A9_de_gorge_du_fort_d%27Uxegney.jpg" decoding="async" width="220" height="147" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/c1/Le_foss%C3%A9_de_gorge_du_fort_d%27Uxegney.jpg/330px-Le_foss%C3%A9_de_gorge_du_fort_d%27Uxegney.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c1/Le_foss%C3%A9_de_gorge_du_fort_d%27Uxegney.jpg/440px-Le_foss%C3%A9_de_gorge_du_fort_d%27Uxegney.jpg 2x" data-file-width="3888" data-file-height="2592" /></a><figcaption>The gorge or interior of <a href="/wiki/Fort_d%27Uxegney" title="Fort d'Uxegney">Fort d'Uxegney</a>, showing the heavily protected accommodation casemates typical of the <a href="/wiki/S%C3%A9r%C3%A9_de_Rivi%C3%A8res_system" title="Séré de Rivières system">Séré de Rivières system</a></figcaption></figure> <p>In the United States, it had been decided at an early stage that it would be impractical to provide landward fortifications for rapidly expanding cities but a considerable investment had been made in seaward defences in the form of multi-tiered casemated batteries, originally based on Montalembert's designs. During the <a href="/wiki/American_Civil_War" title="American Civil War">American Civil War</a> of 1861 to 1865, the exposed masonry of these coastal batteries was found to be vulnerable to modern rifled artillery; <a href="/wiki/Fort_Pulaski" class="mw-redirect" title="Fort Pulaski">Fort Pulaski</a> was quickly breached by only ten of these guns. On the other hand, the hastily constructed earthworks of landward fortifications proved much more resilient; the garrison of <a href="/wiki/Fort_Wagner" title="Fort Wagner">Fort Wagner</a> were able to hold out for 58 days behind ramparts built of sand.<sup id="cite_ref-31" class="reference"><a href="#cite_note-31"><span class="cite-bracket">[</span>31<span class="cite-bracket">]</span></a></sup> </p><p>In France the military establishment clung to the concept of the bastion system. Between 1841 and 1844, an immense bastioned trace, the <a href="/wiki/Thiers_Wall" class="mw-redirect" title="Thiers Wall">Thiers Wall</a>, was built around <a href="/wiki/Paris" title="Paris">Paris</a>. It was a single rampart 21 mi (33 km) long reinforced by 94 bastions. The main approaches to the city were further defended by several outlying bastioned forts, designed for all-round defence but not sited to be mutually supporting. In the <a href="/wiki/Franco-Prussian_War" title="Franco-Prussian War">Franco-Prussian War</a> of 1870, the invading Prussians were able to <a href="/wiki/Siege_of_Paris_(1870%E2%80%9371)" class="mw-redirect" title="Siege of Paris (1870–71)">surround Paris</a> after taking some of the outer forts and then bombard the city and its population with their rifled siege guns, without the need for a costly assault.<sup id="cite_ref-32" class="reference"><a href="#cite_note-32"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup> </p><p>In the aftermath of defeat, the French belatedly adopted a version of the polygonal system in a huge programme of fortification which commenced in 1874, under the direction of General <a href="/wiki/Raymond_Adolphe_S%C3%A9r%C3%A9_de_Rivi%C3%A8res" title="Raymond Adolphe Séré de Rivières">Raymond Adolphe Séré de Rivières</a>. Polygonal forts typical of the <a href="/wiki/S%C3%A9r%C3%A9_de_Rivi%C3%A8res_system" title="Séré de Rivières system">Séré de Rivières system</a> had guns protected by <a href="/wiki/Iron_armour" title="Iron armour">iron armour</a> or revolving <a href="/wiki/Mougin_turret" title="Mougin turret">Mougin turrets</a>. The vulnerable masonry of the accommodation casemates were built facing away from an opponent, protected overhead by large mounds of earth, 18 ft (5.5 m) deep.<sup id="cite_ref-33" class="reference"><a href="#cite_note-33"><span class="cite-bracket">[</span>33<span class="cite-bracket">]</span></a></sup> The programme involved the building of ring fortresses around Paris and to guard border crossings, often surrounding Vauban-era fortifications; the loss of <a href="/wiki/Alsace-Lorraine" class="mw-redirect" title="Alsace-Lorraine">Alsace-Lorraine</a> to the Prussians created the need for a new defensive zone, described as a "barrier of iron".<sup id="cite_ref-34" class="reference"><a href="#cite_note-34"><span class="cite-bracket">[</span>34<span class="cite-bracket">]</span></a></sup> Similar forts were also being built in Germany designed Hans Alexis von Bichler.<sup id="cite_ref-35" class="reference"><a href="#cite_note-35"><span class="cite-bracket">[</span>35<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="The_"torpedo-shell_crisis""><span id="The_.22torpedo-shell_crisis.22"></span>The "torpedo-shell crisis"</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Polygonal_fort&action=edit&section=6" title="Edit section: The "torpedo-shell crisis""><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Pentagonal_Brialmont_fort,_1914.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/67/Pentagonal_Brialmont_fort%2C_1914.jpg/220px-Pentagonal_Brialmont_fort%2C_1914.jpg" decoding="async" width="220" height="87" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/67/Pentagonal_Brialmont_fort%2C_1914.jpg/330px-Pentagonal_Brialmont_fort%2C_1914.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/67/Pentagonal_Brialmont_fort%2C_1914.jpg/440px-Pentagonal_Brialmont_fort%2C_1914.jpg 2x" data-file-width="1016" data-file-height="400" /></a><figcaption>A typical Belgian fort designed by <a href="/wiki/Henri_Alexis_Brialmont" title="Henri Alexis Brialmont">Henri Alexis Brialmont</a> in the 1880s, showing the broadly triangular plan which he favoured</figcaption></figure> <p>From the mid-19th century, chemists produced the first <a href="/wiki/Explosive#High_explosives" title="Explosive">high explosive</a> compounds, as opposed to <a href="/wiki/Explosive#Low_explosives" title="Explosive">low explosives</a> such as <a href="/wiki/Gunpowder" title="Gunpowder">gunpowder</a>. The first of these, <a href="/wiki/Nitroglycerine" class="mw-redirect" title="Nitroglycerine">nitroglycerine</a> and from 1867, <a href="/wiki/Dynamite" title="Dynamite">dynamite</a>, proved to be too unstable to be fired from a gun without exploding in the barrel. In 1885, the French chemist <a href="/wiki/Eug%C3%A8ne_Turpin" title="Eugène Turpin">Eugène Turpin</a>, patented a form of <a href="/wiki/Picric_acid" title="Picric acid">picric acid</a>, which proved stable enough to be used as a blasting charge in artillery shells. These shells had recently evolved from the traditional sphere of iron into a pointed cylinder, at that time known as a "torpedo-shell". The combination of these, combined with new delayed-action fuzes, meant that shells could bury themselves deep under the surface of a fort and then explode with unprecedented force. The realisation that this new technology made even the most modern forts vulnerable was known as the "torpedo-shell crisis". The great powers of continental Europe were forced into vastly expensive programmes of fortification building and rebuilding to designs that were calculated to counter this latest threat.<sup id="cite_ref-36" class="reference"><a href="#cite_note-36"><span class="cite-bracket">[</span>36<span class="cite-bracket">]</span></a></sup> </p><p>In France, the recently completed forts began to be refurbished, with thick layers of concrete reinforcing the ramparts and the roofs of magazines and accommodation spaces. The Belgians had not started their new fortifications when the effectiveness of the new munitions became known and their chief engineer, <a href="/wiki/Henri_Alexis_Brialmont" title="Henri Alexis Brialmont">Henri Alexis Brialmont</a>, was able to incorporate countermeasures in his design.<sup id="cite_ref-37" class="reference"><a href="#cite_note-37"><span class="cite-bracket">[</span>37<span class="cite-bracket">]</span></a></sup> Brialmont forts were triangular in plan and made extensive use of <a href="/wiki/Concrete" title="Concrete">concrete</a> with the main armament mounted in rotating turrets connected by tunnels.<sup id="cite_ref-38" class="reference"><a href="#cite_note-38"><span class="cite-bracket">[</span>38<span class="cite-bracket">]</span></a></sup> The French and Belgians assumed that the new forts must be able to withstand siege guns up to a calibre of 8 in (21 cm) as this was the largest mobile weapon in use.<sup id="cite_ref-39" class="reference"><a href="#cite_note-39"><span class="cite-bracket">[</span>39<span class="cite-bracket">]</span></a></sup> In Germany, after updating their Bichler forts with layers of sand and concrete and building others in the style of Brialmont, a new design emerged, in which fort artillery and infantry positions would be dispersed in the landscape, connected only by trenches or tunnels and without a continuous enceinte. This type of fortified position was called a <span title="German-language text"><i lang="de">Feste</i></span> and was the result of the work of several German theorists but came to fruition under <a href="/wiki/Colmar_Freiherr_von_der_Goltz" title="Colmar Freiherr von der Goltz">Colmar Freiherr von der Goltz</a> who was appointed Inspector-General of Fortifications in 1898.<sup id="cite_ref-40" class="reference"><a href="#cite_note-40"><span class="cite-bracket">[</span>40<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="World_Wars">World Wars</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Polygonal_fort&action=edit&section=7" title="Edit section: World Wars"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Ruins_of_Fort_Loucin_in_the_Fortress_of_Liege_1914.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/c8/Ruins_of_Fort_Loucin_in_the_Fortress_of_Liege_1914.jpg/220px-Ruins_of_Fort_Loucin_in_the_Fortress_of_Liege_1914.jpg" decoding="async" width="220" height="143" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/c8/Ruins_of_Fort_Loucin_in_the_Fortress_of_Liege_1914.jpg/330px-Ruins_of_Fort_Loucin_in_the_Fortress_of_Liege_1914.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/c8/Ruins_of_Fort_Loucin_in_the_Fortress_of_Liege_1914.jpg/440px-Ruins_of_Fort_Loucin_in_the_Fortress_of_Liege_1914.jpg 2x" data-file-width="800" data-file-height="519" /></a><figcaption>Damage from a 42 cm howitzer to a <a href="/wiki/Mougin_turret" title="Mougin turret">Mougin turret</a> at <a href="/wiki/Fort_de_Loncin" title="Fort de Loncin">Fort de Loncin</a> during the <a href="/wiki/Battle_of_Li%C3%A8ge" title="Battle of Liège">Battle of Liège</a> in August 1914</figcaption></figure> <div class="mw-heading mw-heading3"><h3 id="First_World_War">First World War</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Polygonal_fort&action=edit&section=8" title="Edit section: First World War"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>At the start of the <a href="/wiki/First_World_War" class="mw-redirect" title="First World War">First World War</a> in August 1914, the German Army crossed into neutral Belgium with the object of outflanking the French border fortifications. In their path was the <a href="/wiki/Fortified_position_of_Li%C3%A8ge" title="Fortified position of Liège">fortified position of Liège</a>, a ring fortress built by Brialmont with a circumference of 29 mi (46 km) which the Germans reached on 4 August. Repeated attempts to pass massed infantry through the intervals between the forts resulted in the capture of the city of Liège on 7 August, at the cost of 47,500 German casualties and without any of the forts being taken.<sup id="cite_ref-41" class="reference"><a href="#cite_note-41"><span class="cite-bracket">[</span>41<span class="cite-bracket">]</span></a></sup> The forts were only subdued by the arrival of super-heavy <a href="/wiki/42_cm_Gamma_M%C3%B6rser" class="mw-redirect" title="42 cm Gamma Mörser">42 cm Gamma Mörser</a> siege howitzers and other large weapons, which were capable of smashing the armoured turrets and penetrating the concrete living spaces; the last fort surrendering on 16 August.<sup id="cite_ref-42" class="reference"><a href="#cite_note-42"><span class="cite-bracket">[</span>42<span class="cite-bracket">]</span></a></sup> The <a href="/wiki/Fortified_position_of_Namur" title="Fortified position of Namur">fortified position of Namur</a> was demolished in the same fashion a few days later and <a href="/wiki/National_Redoubt_(Belgium)" title="National Redoubt (Belgium)">that at Antwerp</a> only survived for longer because fewer resources were directed against it.<sup id="cite_ref-43" class="reference"><a href="#cite_note-43"><span class="cite-bracket">[</span>43<span class="cite-bracket">]</span></a></sup> </p> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Kauno_Tvirtoves_generalinis_planas.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/3/3a/Kauno_Tvirtoves_generalinis_planas.jpg/220px-Kauno_Tvirtoves_generalinis_planas.jpg" decoding="async" width="220" height="170" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/3/3a/Kauno_Tvirtoves_generalinis_planas.jpg/330px-Kauno_Tvirtoves_generalinis_planas.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/3/3a/Kauno_Tvirtoves_generalinis_planas.jpg 2x" data-file-width="397" data-file-height="307" /></a><figcaption>The Russian ring fortress at <a href="/wiki/Kaunas" title="Kaunas">Kaunas</a>, which was abandoned by the garrison after Forts 1, 2 and 3 were lost to German assaults in July and August 1915</figcaption></figure> <p>On the <a href="/wiki/Eastern_Front_(World_War_I)" title="Eastern Front (World War I)">Eastern Front</a>, most polygonal fortifications were also quickly overcome by heavy artillery. The <a href="/wiki/Kaunas_Fortress" title="Kaunas Fortress">Kaunas Fortress</a> (now in <a href="/wiki/Lithuania" title="Lithuania">Lithuania</a>) was the most expensive fortification in the Russian Empire, but a modernisation programme was incomplete. In July 1915, German assaults concentrated on three un-modernised forts in the southwest sector. Following the loss of these forts the garrison abandoned the entire fortress, prompted by the desertion of their commanding officer on the previous day, the assault having lasted only eleven days.<sup id="cite_ref-44" class="reference"><a href="#cite_note-44"><span class="cite-bracket">[</span>44<span class="cite-bracket">]</span></a></sup> Another Russian ring fortress at Novogeorgievsk, later renamed <a href="/wiki/Modlin_Fortress" title="Modlin Fortress">Modlin</a>, which guarded the northern approach to <a href="/wiki/Warsaw" title="Warsaw">Warsaw</a>, fell after <a href="/wiki/Siege_of_Novogeorgievsk" title="Siege of Novogeorgievsk">a siege of 10 days</a> in August 1915, with the loss of 90,000 men taken prisoner and 1,600 guns.<sup id="cite_ref-45" class="reference"><a href="#cite_note-45"><span class="cite-bracket">[</span>45<span class="cite-bracket">]</span></a></sup> The largest Austro-Hungarian fortification was <a href="/wiki/Przemy%C5%9Bl_Fortress" title="Przemyśl Fortress">Przemyśl Fortress</a> which protected the province of <a href="/wiki/Eastern_Galicia" title="Eastern Galicia">Eastern Galicia</a> and had a ring of twenty five modern polygonal forts. An invading Russian army besieged the fortress, but initially lacked heavy artillery and were short of ammunition for their field guns. An initial infantry assault in September 1914 was repulsed with heavy Russian losses,<sup id="cite_ref-46" class="reference"><a href="#cite_note-46"><span class="cite-bracket">[</span>46<span class="cite-bracket">]</span></a></sup> but the fortress was finally surrendered in the following March, after both a relief attempt and a <a href="/wiki/Breakout_(military)" title="Breakout (military)">breakout</a> had failed.<sup id="cite_ref-47" class="reference"><a href="#cite_note-47"><span class="cite-bracket">[</span>47<span class="cite-bracket">]</span></a></sup> </p> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Fort_Douaumont_Ende_1916.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/f/f5/Fort_Douaumont_Ende_1916.jpg/220px-Fort_Douaumont_Ende_1916.jpg" decoding="async" width="220" height="204" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/f/f5/Fort_Douaumont_Ende_1916.jpg/330px-Fort_Douaumont_Ende_1916.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/f/f5/Fort_Douaumont_Ende_1916.jpg/440px-Fort_Douaumont_Ende_1916.jpg 2x" data-file-width="1557" data-file-height="1445" /></a><figcaption>An aerial photograph of Fort Douaumont at the close of the <a href="/wiki/Battle_of_Verdun" title="Battle of Verdun">Battle of Verdun</a> in December 1916, following months of bombardment from both sides</figcaption></figure> <p>Following these failures, the French high command concluded that fixed fortifications were obsolete and they began the process of disarming their forts, since there was a grave shortage of medium artillery pieces in their field armies.<sup id="cite_ref-48" class="reference"><a href="#cite_note-48"><span class="cite-bracket">[</span>48<span class="cite-bracket">]</span></a></sup> In February 1916, the Germans began the <a href="/wiki/Battle_of_Verdun" title="Battle of Verdun">Battle of Verdun</a>, hoping to force the French to squander their forces in costly counter-attacks in an effort to regain it. They found that the Verdun forts, which had been recently upgraded with extra layers of concrete and sand, were resistant to their heaviest shells. <a href="/wiki/Fort_Douaumont" title="Fort Douaumont">Fort Douaumont</a> was captured, almost by accident, by a small party of Germans who climbed through an unattended embrasure, the rest of the forts could not permanently be subdued and the offensive was eventually called off in July after huge casualties on both sides.<sup id="cite_ref-49" class="reference"><a href="#cite_note-49"><span class="cite-bracket">[</span>49<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Inter-war_developments">Inter-war developments</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Polygonal_fort&action=edit&section=9" title="Edit section: Inter-war developments"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>After the war, the apparent success of the Verdun forts led the French government to re-fortify the eastern border. Rather than build new polygonal forts, the method chosen was a developed version of the German <span title="German-language text"><i lang="de">Feste</i></span> system of dispersed strongpoints connected by tunnels to a central underground barracks, all concealed in the landscape. This concept known to the French as <span title="German-language text"><i lang="de">fort palmé</i></span> because the elements of the fort were analogous to the fingers of a hand.<sup id="cite_ref-50" class="reference"><a href="#cite_note-50"><span class="cite-bracket">[</span>50<span class="cite-bracket">]</span></a></sup> The system became known as the <a href="/wiki/Maginot_Line" title="Maginot Line">Maginot Line</a>, after the French Minister of War, who had initiated the project in 1930. Where the Maginot Line coincided with Séré de Rivières forts, new concrete casemates were constructed inside the old works.<sup id="cite_ref-Kaufmann_Kaufmann_Lang_p.208_51-0" class="reference"><a href="#cite_note-Kaufmann_Kaufmann_Lang_p.208-51"><span class="cite-bracket">[</span>51<span class="cite-bracket">]</span></a></sup> In Belgium, a series of commissions decided that a new line of fortifications should be constructed at Liège, while some of the old forts there should be modernised. Three new forts were constructed which were developed forms of the old Brialmont polygonal forts. The fourth and largest, <a href="/wiki/Fort_Eben-Emael" class="mw-redirect" title="Fort Eben-Emael">Fort Eben-Emael</a>, had its enceinte defined by the great cutting of the <a href="/wiki/Albert_Canal" title="Albert Canal">Albert Canal</a>.<sup id="cite_ref-52" class="reference"><a href="#cite_note-52"><span class="cite-bracket">[</span>52<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Second_World_War">Second World War</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Polygonal_fort&action=edit&section=10" title="Edit section: Second World War"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size mw-halign-left" typeof="mw:File/Thumb"><a href="/wiki/File:Dzie%C5%82o_D-10_3.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/d/da/Dzie%C5%82o_D-10_3.jpg/220px-Dzie%C5%82o_D-10_3.jpg" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/da/Dzie%C5%82o_D-10_3.jpg/330px-Dzie%C5%82o_D-10_3.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/da/Dzie%C5%82o_D-10_3.jpg/440px-Dzie%C5%82o_D-10_3.jpg 2x" data-file-width="4896" data-file-height="3672" /></a><figcaption>A concrete casemate at Fort XVIII of the <a href="/wiki/Modlin_Fortress" title="Modlin Fortress">Modlin Fortress</a>, destroyed during the <a href="/wiki/Battle_of_Modlin" title="Battle of Modlin">Battle of Modlin</a> in 1939</figcaption></figure> <p>The war opened with the German <a href="/wiki/Invasion_of_Poland" title="Invasion of Poland">invasion of Poland</a> on 1 September 1939; by 13 September, Warsaw and the partly-modernised fortress of Modlin had been surrounded. The fortress was separated from Warsaw on 22 September and despite numerous German infantry assaults supported by heavy artillery and dive bombing, Modlin was not surrendered until 29 September after receiving the news that Warsaw had fallen.<sup id="cite_ref-53" class="reference"><a href="#cite_note-53"><span class="cite-bracket">[</span>53<span class="cite-bracket">]</span></a></sup> </p><p>On 10 May 1940, German forces attacked the new Belgian forts, quickly <a href="/wiki/Battle_of_Fort_Eben-Emael" class="mw-redirect" title="Battle of Fort Eben-Emael">neutralising Eben-Emael by airborne assault</a>. The three other forts were bombarded by <a href="/wiki/Skoda_305_mm_Model_1911" title="Skoda 305 mm Model 1911">305 mm howitzers</a> and <a href="/wiki/Dive-bomber" class="mw-redirect" title="Dive-bomber">dive-bombers</a> and each repulsed several infantry assaults. Two of the forts surrendered on 21 May and the last, <a href="/wiki/Fort_de_Battice" title="Fort de Battice">Fort de Battice</a>, on the following day, having been by-passed by the main German thrust.<sup id="cite_ref-54" class="reference"><a href="#cite_note-54"><span class="cite-bracket">[</span>54<span class="cite-bracket">]</span></a></sup> Modernised French polygonal forts at <a href="/wiki/Maubeuge" title="Maubeuge">Maubeuge</a> were attacked on 19 May and were surrendered after their gun turrets and observation domes had been knocked out with <a href="/wiki/Anti-tank_gun" title="Anti-tank gun">anti-tank guns</a> and demolition charges.<sup id="cite_ref-Kaufmann_Kaufmann_Lang_p.208_51-1" class="reference"><a href="#cite_note-Kaufmann_Kaufmann_Lang_p.208-51"><span class="cite-bracket">[</span>51<span class="cite-bracket">]</span></a></sup> Late in the war, the ring <a href="/wiki/Fortifications_of_Metz" title="Fortifications of Metz">fortifications of Metz</a> were hastily prepared for defence by German forces and were attacked by the <a href="/wiki/United_States_Army_Central" title="United States Army Central">Third Army</a> in mid-September 1944 in the <a href="/wiki/Battle_of_Metz" title="Battle of Metz">Battle of Metz</a>; the last fort surrendered nearly three months later.<sup id="cite_ref-55" class="reference"><a href="#cite_note-55"><span class="cite-bracket">[</span>55<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Polygonal_fort&action=edit&section=11" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-columns references-column-width" style="column-width: 30em;"> <ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text">Hogg, pp. 51–52</span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text">Ostwald, p. 12</span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text">Duffy, p. 41</span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text">Royal Military Academy p. 143</span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text">Hogg p. 73</span> </li> <li id="cite_note-:0-6"><span class="mw-cite-backlink">^ <a href="#cite_ref-:0_6-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-:0_6-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">Wade, p. 110</span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text">Duffy p. 160</span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text">Lloyd & Marsh, p. 114</span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text">Duffy p. 163</span> </li> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text">Spiteri pp. 6-11</span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text">Spiteri p. 71</span> </li> <li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text">Lloyd & Marsh, pp. 125–127</span> </li> <li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text">Lepage p. 96</span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text">Wade p. 111</span> </li> <li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text">Hogg p. 78</span> </li> <li id="cite_note-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-16">^</a></b></span> <span class="reference-text">Royal Military Academy pp. 127–128</span> </li> <li id="cite_note-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-17">^</a></b></span> <span class="reference-text">Lepage pp. 147–148</span> </li> <li id="cite_note-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-18">^</a></b></span> <span class="reference-text">Kaufmann & Kaufmann p. 7</span> </li> <li id="cite_note-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-19">^</a></b></span> <span class="reference-text">Kaufmann & Kaufmann p. 9</span> </li> <li id="cite_note-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-20">^</a></b></span> <span class="reference-text">Douglas, p. 126</span> </li> <li id="cite_note-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-21">^</a></b></span> <span class="reference-text">Royal Military Academy pp. 132–133</span> </li> <li id="cite_note-22"><span class="mw-cite-backlink"><b><a href="#cite_ref-22">^</a></b></span> <span class="reference-text">Kenyon, p. 3</span> </li> <li id="cite_note-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-23">^</a></b></span> <span class="reference-text">Lloyd, p. 98</span> </li> <li id="cite_note-24"><span class="mw-cite-backlink"><b><a href="#cite_ref-24">^</a></b></span> <span class="reference-text">Royal Military Academy p. 132</span> </li> <li id="cite_note-25"><span class="mw-cite-backlink"><b><a href="#cite_ref-25">^</a></b></span> <span class="reference-text">Hogg pp. 79–81</span> </li> <li id="cite_note-26"><span class="mw-cite-backlink"><b><a href="#cite_ref-26">^</a></b></span> <span class="reference-text">Hogg, pp. 80–82</span> </li> <li id="cite_note-27"><span class="mw-cite-backlink"><b><a href="#cite_ref-27">^</a></b></span> <span class="reference-text">Kinard, p. 222</span> </li> <li id="cite_note-28"><span class="mw-cite-backlink"><b><a href="#cite_ref-28">^</a></b></span> <span class="reference-text">Royal Military Academy, p. 150</span> </li> <li id="cite_note-29"><span class="mw-cite-backlink"><b><a href="#cite_ref-29">^</a></b></span> <span class="reference-text">Crick 2012, pp. 46–47</span> </li> <li id="cite_note-30"><span class="mw-cite-backlink"><b><a href="#cite_ref-30">^</a></b></span> <span class="reference-text">Dyer 2003, p. 7</span> </li> <li id="cite_note-31"><span class="mw-cite-backlink"><b><a href="#cite_ref-31">^</a></b></span> <span class="reference-text">Hogg, p. 101</span> </li> <li id="cite_note-32"><span class="mw-cite-backlink"><b><a href="#cite_ref-32">^</a></b></span> <span class="reference-text">Hogg, p. 102</span> </li> <li id="cite_note-33"><span class="mw-cite-backlink"><b><a href="#cite_ref-33">^</a></b></span> <span class="reference-text">Hogg, p. 104</span> </li> <li id="cite_note-34"><span class="mw-cite-backlink"><b><a href="#cite_ref-34">^</a></b></span> <span class="reference-text">Kaufmann & Kaufmann (Neutral States), p. xiii</span> </li> <li id="cite_note-35"><span class="mw-cite-backlink"><b><a href="#cite_ref-35">^</a></b></span> <span class="reference-text">Kaufmann & Kaufmann (Central States), p. 47</span> </li> <li id="cite_note-36"><span class="mw-cite-backlink"><b><a href="#cite_ref-36">^</a></b></span> <span class="reference-text">Donnel, pp. 7–8</span> </li> <li id="cite_note-37"><span class="mw-cite-backlink"><b><a href="#cite_ref-37">^</a></b></span> <span class="reference-text">Donnel, p. 8</span> </li> <li id="cite_note-38"><span class="mw-cite-backlink"><b><a href="#cite_ref-38">^</a></b></span> <span class="reference-text">Donnel, p. 12</span> </li> <li id="cite_note-39"><span class="mw-cite-backlink"><b><a href="#cite_ref-39">^</a></b></span> <span class="reference-text">Hogg, pp. 103–105</span> </li> <li id="cite_note-40"><span class="mw-cite-backlink"><b><a href="#cite_ref-40">^</a></b></span> <span class="reference-text">Kaufmann and Kaufmann (Central States), pp. 30–31</span> </li> <li id="cite_note-41"><span class="mw-cite-backlink"><b><a href="#cite_ref-41">^</a></b></span> <span class="reference-text"> Kaufmann & Kaufmann (Neutral States), pp. 94</span> </li> <li id="cite_note-42"><span class="mw-cite-backlink"><b><a href="#cite_ref-42">^</a></b></span> <span class="reference-text">Hogg, pp. 118–119</span> </li> <li id="cite_note-43"><span class="mw-cite-backlink"><b><a href="#cite_ref-43">^</a></b></span> <span class="reference-text"> Kaufmann & Kaufmann (Neutral States), p. 94</span> </li> <li id="cite_note-44"><span class="mw-cite-backlink"><b><a href="#cite_ref-44">^</a></b></span> <span class="reference-text">Boyd 2017, pp. 111-112</span> </li> <li id="cite_note-45"><span class="mw-cite-backlink"><b><a href="#cite_ref-45">^</a></b></span> <span class="reference-text">DiNardo 2010, p. 130</span> </li> <li id="cite_note-46"><span class="mw-cite-backlink"><b><a href="#cite_ref-46">^</a></b></span> <span class="reference-text">Boyd 2017, pp. 87-88</span> </li> <li id="cite_note-47"><span class="mw-cite-backlink"><b><a href="#cite_ref-47">^</a></b></span> <span class="reference-text">Boyd 2017, pp. 94-95</span> </li> <li id="cite_note-48"><span class="mw-cite-backlink"><b><a href="#cite_ref-48">^</a></b></span> <span class="reference-text">Hogg, p. 121</span> </li> <li id="cite_note-49"><span class="mw-cite-backlink"><b><a href="#cite_ref-49">^</a></b></span> <span class="reference-text">Hogg, pp. 121–122</span> </li> <li id="cite_note-50"><span class="mw-cite-backlink"><b><a href="#cite_ref-50">^</a></b></span> <span class="reference-text">Kaufmann & Kaufmann (Fortress France), p. 14</span> </li> <li id="cite_note-Kaufmann_Kaufmann_Lang_p.208-51"><span class="mw-cite-backlink">^ <a href="#cite_ref-Kaufmann_Kaufmann_Lang_p.208_51-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Kaufmann_Kaufmann_Lang_p.208_51-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">Kaufmann, Kaufmann & Lang, p. 208</span> </li> <li id="cite_note-52"><span class="mw-cite-backlink"><b><a href="#cite_ref-52">^</a></b></span> <span class="reference-text">Dunstan (Introduction)</span> </li> <li id="cite_note-53"><span class="mw-cite-backlink"><b><a href="#cite_ref-53">^</a></b></span> <span class="reference-text">Moorhouse 2019, pp. 159, 194, 255</span> </li> <li id="cite_note-54"><span class="mw-cite-backlink"><b><a href="#cite_ref-54">^</a></b></span> <span class="reference-text">Kauffmann (Fortress Europe), pp. 116–117</span> </li> <li id="cite_note-55"><span class="mw-cite-backlink"><b><a href="#cite_ref-55">^</a></b></span> <span class="reference-text">Zaloga, p. 70</span> </li> </ol></div> <div class="mw-heading mw-heading3"><h3 id="Sources">Sources</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Polygonal_fort&action=edit&section=12" title="Edit section: Sources"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFBoyd2017" class="citation book cs1">Boyd, Douglas (2017). <i>The Other First World War: The Blood-Soaked Russian Fronts 1914-1922</i>. Stroud, Gloucestershire: The History Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7509-6405-0" title="Special:BookSources/978-0-7509-6405-0"><bdi>978-0-7509-6405-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Other+First+World+War%3A+The+Blood-Soaked+Russian+Fronts+1914-1922&rft.place=Stroud%2C+Gloucestershire&rft.pub=The+History+Press&rft.date=2017&rft.isbn=978-0-7509-6405-0&rft.aulast=Boyd&rft.aufirst=Douglas&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCrick2012" class="citation book cs1">Crick, Timothy (2012). <i>Ramparts of Empire: The Fortifications of Sir William Jervois, Royal Engineer 1821–1897</i>. Exeter: University of Exeter Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-905816-04-0" title="Special:BookSources/978-1-905816-04-0"><bdi>978-1-905816-04-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Ramparts+of+Empire%3A+The+Fortifications+of+Sir+William+Jervois%2C+Royal+Engineer+1821%E2%80%931897&rft.place=Exeter&rft.pub=University+of+Exeter+Press&rft.date=2012&rft.isbn=978-1-905816-04-0&rft.aulast=Crick&rft.aufirst=Timothy&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDiNardo2010" class="citation book cs1">DiNardo, Richard (2010). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=Pty-r-7KnCoC&pg=PA117"><i>Breakthrough: The Gorlice-Tarnow Campaign, 1915</i></a>. Santa Barbara, CA: Praeger. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0275991104" title="Special:BookSources/978-0275991104"><bdi>978-0275991104</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Breakthrough%3A+The+Gorlice-Tarnow+Campaign%2C+1915&rft.place=Santa+Barbara%2C+CA&rft.pub=Praeger&rft.date=2010&rft.isbn=978-0275991104&rft.aulast=DiNardo&rft.aufirst=Richard&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DPty-r-7KnCoC%26pg%3DPA117&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDonnel2013" class="citation book cs1">Donnel, Clayton (2013). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=zYZsBAAAQBAJ&pg=PA215"><i>Breaking the Fortress Line 1914</i></a>. Barnsley, England: Pen & Sword Military. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-84884-813-9" title="Special:BookSources/978-1-84884-813-9"><bdi>978-1-84884-813-9</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Breaking+the+Fortress+Line+1914&rft.place=Barnsley%2C+England&rft.pub=Pen+%26+Sword+Military&rft.date=2013&rft.isbn=978-1-84884-813-9&rft.aulast=Donnel&rft.aufirst=Clayton&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DzYZsBAAAQBAJ%26pg%3DPA215&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDonnel2011" class="citation book cs1">Donnel, Clayton (2011). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=uTe3CwAAQBAJ&pg=PA12"><i>The Fortifications of Verdun 1874–1917</i></a>. Oxford: Osprey. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-84908-412-3" title="Special:BookSources/978-1-84908-412-3"><bdi>978-1-84908-412-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Fortifications+of+Verdun+1874%E2%80%931917&rft.place=Oxford&rft.pub=Osprey&rft.date=2011&rft.isbn=978-1-84908-412-3&rft.aulast=Donnel&rft.aufirst=Clayton&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DuTe3CwAAQBAJ%26pg%3DPA12&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDouglas1859" class="citation book cs1"><a href="/wiki/Howard_Douglas" title="Howard Douglas">Douglas, Howard</a> (1859). <a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=hvd.32044020538583;view=1up;seq=3"><i>Observations on Modern Systems of Fortification, Including that Proposed by M. Carnot, and a Comparison of the Polygonal with the Bastion System; to which are Added, some Reflections on Intrenched Positions, and a Tract on the Naval, Littoral, and Internal Defence of England</i></a>. London: John Murray. <a href="/wiki/OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/9955860">9955860</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Observations+on+Modern+Systems+of+Fortification%2C+Including+that+Proposed+by+M.+Carnot%2C+and+a+Comparison+of+the+Polygonal+with+the+Bastion+System%3B+to+which+are+Added%2C+some+Reflections+on+Intrenched+Positions%2C+and+a+Tract+on+the+Naval%2C+Littoral%2C+and+Internal+Defence+of+England&rft.place=London&rft.pub=John+Murray&rft.date=1859&rft_id=info%3Aoclcnum%2F9955860&rft.aulast=Douglas&rft.aufirst=Howard&rft_id=https%3A%2F%2Fbabel.hathitrust.org%2Fcgi%2Fpt%3Fid%3Dhvd.32044020538583%3Bview%3D1up%3Bseq%3D3&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDuffy2017" class="citation book cs1"><a href="/wiki/Christopher_Duffy" title="Christopher Duffy">Duffy, Christopher</a> (2017). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=nuioCgAAQBAJ&pg=PA160"><i>The Fortress in the Age of Vauban and Frederick the Great 1660–1789</i></a>. London: Routledge. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-138-92464-2" title="Special:BookSources/978-1-138-92464-2"><bdi>978-1-138-92464-2</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Fortress+in+the+Age+of+Vauban+and+Frederick+the+Great+1660%E2%80%931789&rft.place=London&rft.pub=Routledge&rft.date=2017&rft.isbn=978-1-138-92464-2&rft.aulast=Duffy&rft.aufirst=Christopher&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DnuioCgAAQBAJ%26pg%3DPA160&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDunstan2005" class="citation book cs1">Dunstan, Simon (2005). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=nkziCwAAQBAJ"><i>Fort Eben Emael: The Key to Hitler's Victory in the West</i></a>. Oxford: Osprey. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-84176-821-2" title="Special:BookSources/978-1-84176-821-2"><bdi>978-1-84176-821-2</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Fort+Eben+Emael%3A+The+Key+to+Hitler%27s+Victory+in+the+West&rft.place=Oxford&rft.pub=Osprey&rft.date=2005&rft.isbn=978-1-84176-821-2&rft.aulast=Dunstan&rft.aufirst=Simon&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DnkziCwAAQBAJ&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDyer2003" class="citation book cs1">Dyer, Nick (2003). <i>British Fortification in the late 19th and early 20th Centuries</i>. Fareham: The Palmerston Forts Society. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-9523634-6-0" title="Special:BookSources/978-0-9523634-6-0"><bdi>978-0-9523634-6-0</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=British+Fortification+in+the+late+19th+and+early+20th+Centuries&rft.place=Fareham&rft.pub=The+Palmerston+Forts+Society&rft.date=2003&rft.isbn=978-0-9523634-6-0&rft.aulast=Dyer&rft.aufirst=Nick&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHogg1975" class="citation book cs1"><a href="/wiki/Ian_V._Hogg" title="Ian V. Hogg">Hogg, Ian V.</a> (1975). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=fwhUAAAAMAAJ"><i>Fortress: A History of Military Defence</i></a>. London: Macdonald and Jane's. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-356-08122-2" title="Special:BookSources/0-356-08122-2"><bdi>0-356-08122-2</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Fortress%3A+A+History+of+Military+Defence&rft.place=London&rft.pub=Macdonald+and+Jane%27s&rft.date=1975&rft.isbn=0-356-08122-2&rft.aulast=Hogg&rft.aufirst=Ian+V.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DfwhUAAAAMAAJ&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKinard2007" class="citation book cs1">Kinard, Jeff (2007). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=iH4j8abhD1cC&pg=PA222"><i>Artillery: An Illustrated History of Its Impact</i></a>. Santa Barbara, CA: ABC-CLIO. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-85109-556-8" title="Special:BookSources/978-1-85109-556-8"><bdi>978-1-85109-556-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Artillery%3A+An+Illustrated+History+of+Its+Impact&rft.place=Santa+Barbara%2C+CA&rft.pub=ABC-CLIO&rft.date=2007&rft.isbn=978-1-85109-556-8&rft.aulast=Kinard&rft.aufirst=Jeff&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DiH4j8abhD1cC%26pg%3DPA222&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKaufmannJurga1999" class="citation book cs1">Kaufmann, J. E.; Jurga, R. M. (1999). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=Gmw0ngEACAAJ"><i>Fortress Europe: European Fortifications Of World War II</i></a>. Conshohocken, PA: Combined Publishing. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-58097-000-6" title="Special:BookSources/978-1-58097-000-6"><bdi>978-1-58097-000-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Fortress+Europe%3A+European+Fortifications+Of+World+War+II&rft.place=Conshohocken%2C+PA&rft.pub=Combined+Publishing&rft.date=1999&rft.isbn=978-1-58097-000-6&rft.aulast=Kaufmann&rft.aufirst=J.+E.&rft.au=Jurga%2C+R.+M.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DGmw0ngEACAAJ&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKaufmannKaufmann2008" class="citation book cs1">Kaufmann, J. E.; Kaufmann, H. W. (2008). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=8ea-wpeWplQC&pg=PA14"><i>Fortress France: The Maginot Line and French Defenses in World War II</i></a>. Mechanicsburg, PA: Stackpole Books. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-8117-3395-3" title="Special:BookSources/978-0-8117-3395-3"><bdi>978-0-8117-3395-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Fortress+France%3A+The+Maginot+Line+and+French+Defenses+in+World+War+II&rft.place=Mechanicsburg%2C+PA&rft.pub=Stackpole+Books&rft.date=2008&rft.isbn=978-0-8117-3395-3&rft.aulast=Kaufmann&rft.aufirst=J.+E.&rft.au=Kaufmann%2C+H.+W.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D8ea-wpeWplQC%26pg%3DPA14&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKaufmannKaufmann2014" class="citation book cs1">Kaufmann, J. E.; Kaufmann, H. W. (2014). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=xQJtBQAAQBAJ&pg=PA47"><i>The Forts and Fortifications of Europe 1815–1945: The Central States: Germany, Austria-Hungary and Czechoslovakia</i></a>. Barnsley, England: Pen & Sword Military. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-84884-806-1" title="Special:BookSources/978-1-84884-806-1"><bdi>978-1-84884-806-1</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Forts+and+Fortifications+of+Europe+1815%E2%80%931945%3A+The+Central+States%3A+Germany%2C+Austria-Hungary+and+Czechoslovakia&rft.place=Barnsley%2C+England&rft.pub=Pen+%26+Sword+Military&rft.date=2014&rft.isbn=978-1-84884-806-1&rft.aulast=Kaufmann&rft.aufirst=J.+E.&rft.au=Kaufmann%2C+H.+W.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DxQJtBQAAQBAJ%26pg%3DPA47&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKaufmannKaufmann2014" class="citation book cs1">Kaufmann, J. E.; Kaufmann, H. W. (2014). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=NmZtBQAAQBAJ&pg=PR6"><i>The Forts and Fortifications of Europe 1815–1945: The Neutral States</i></a>. Barnsley, England: Pen & Sword Military. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-78346-392-3" title="Special:BookSources/978-1-78346-392-3"><bdi>978-1-78346-392-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Forts+and+Fortifications+of+Europe+1815%E2%80%931945%3A+The+Neutral+States&rft.place=Barnsley%2C+England&rft.pub=Pen+%26+Sword+Military&rft.date=2014&rft.isbn=978-1-78346-392-3&rft.aulast=Kaufmann&rft.aufirst=J.+E.&rft.au=Kaufmann%2C+H.+W.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DNmZtBQAAQBAJ%26pg%3DPR6&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKaufmannKaufmann2016" class="citation book cs1">Kaufmann, J. E.; Kaufmann, H. W. (2016). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=DTZmDAAAQBAJ&pg=PA107"><i>Verdun 1916: The Renaissance of the Fortress</i></a>. Barnsley, England: Pen & Sword Military. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-4738-2702-8" title="Special:BookSources/978-1-4738-2702-8"><bdi>978-1-4738-2702-8</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Verdun+1916%3A+The+Renaissance+of+the+Fortress&rft.place=Barnsley%2C+England&rft.pub=Pen+%26+Sword+Military&rft.date=2016&rft.isbn=978-1-4738-2702-8&rft.aulast=Kaufmann&rft.aufirst=J.+E.&rft.au=Kaufmann%2C+H.+W.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DDTZmDAAAQBAJ%26pg%3DPA107&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKaufmannKaufmannLang2011" class="citation book cs1">Kaufmann, J. E.; Kaufmann, H. W.; Lang, Patrice (2011). <span class="id-lock-registration" title="Free registration required"><a rel="nofollow" class="external text" href="https://archive.org/details/maginotlinehisto0000kauf"><i>The Maginot Line: History and Guide</i></a></span>. Barnsley, England: Pen & Sword Military. p. <a rel="nofollow" class="external text" href="https://archive.org/details/maginotlinehisto0000kauf/page/208">208</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-84884-068-3" title="Special:BookSources/978-1-84884-068-3"><bdi>978-1-84884-068-3</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=The+Maginot+Line%3A+History+and+Guide&rft.place=Barnsley%2C+England&rft.pages=208&rft.pub=Pen+%26+Sword+Military&rft.date=2011&rft.isbn=978-1-84884-068-3&rft.aulast=Kaufmann&rft.aufirst=J.+E.&rft.au=Kaufmann%2C+H.+W.&rft.au=Lang%2C+Patrice&rft_id=https%3A%2F%2Farchive.org%2Fdetails%2Fmaginotlinehisto0000kauf&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLepage2010" class="citation book cs1">Lepage, Jean-Denis G. G. (2010). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=aeVAPShsbTMC&pg=PA96"><i>French Fortifications, 1715–1815: An Illustrated History</i></a>. Jefferson, NC: McFarland & Company Inc. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7864-4477-9" title="Special:BookSources/978-0-7864-4477-9"><bdi>978-0-7864-4477-9</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=French+Fortifications%2C+1715%E2%80%931815%3A+An+Illustrated+History&rft.place=Jefferson%2C+NC&rft.pub=McFarland+%26+Company+Inc.&rft.date=2010&rft.isbn=978-0-7864-4477-9&rft.aulast=Lepage&rft.aufirst=Jean-Denis+G.+G.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DaeVAPShsbTMC%26pg%3DPA96&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLloyd1887" class="citation book cs1">Lloyd, E. M. (1887). <a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=mdp.39015010775750;view=2up;seq=134;size=125"><i>Vauban, Montalembert, Carnot: Engineer Studies</i></a>. London: Chapman and Hall.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Vauban%2C+Montalembert%2C+Carnot%3A+Engineer+Studies&rft.place=London&rft.pub=Chapman+and+Hall&rft.date=1887&rft.aulast=Lloyd&rft.aufirst=E.+M.&rft_id=https%3A%2F%2Fbabel.hathitrust.org%2Fcgi%2Fpt%3Fid%3Dmdp.39015010775750%3Bview%3D2up%3Bseq%3D134%3Bsize%3D125&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMahan1898" class="citation book cs1"><a href="/wiki/Dennis_Hart_Mahan" title="Dennis Hart Mahan">Mahan, D. H.</a> (1898). <a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=mdp.39015034621907;view=1up;seq=107"><i>Mahan's Permanent Fortifications</i></a>. New York: John Wiley & Sons. <a href="/wiki/OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/13366942">13366942</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Mahan%27s+Permanent+Fortifications&rft.place=New+York&rft.pub=John+Wiley+%26+Sons&rft.date=1898&rft_id=info%3Aoclcnum%2F13366942&rft.aulast=Mahan&rft.aufirst=D.+H.&rft_id=https%3A%2F%2Fbabel.hathitrust.org%2Fcgi%2Fpt%3Fid%3Dmdp.39015034621907%3Bview%3D1up%3Bseq%3D107&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMoorhouse2019" class="citation book cs1"><a href="/wiki/Roger_Moorhouse" title="Roger Moorhouse">Moorhouse, Roger</a> (2019). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=8cx9DwAAQBAJ"><i>First to Fight: The Polish War 1939</i></a>. London: Bodley Head. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1847924605" title="Special:BookSources/978-1847924605"><bdi>978-1847924605</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=First+to+Fight%3A+The+Polish+War+1939&rft.place=London&rft.pub=Bodley+Head&rft.date=2019&rft.isbn=978-1847924605&rft.aulast=Moorhouse&rft.aufirst=Roger&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D8cx9DwAAQBAJ&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFOswald2007" class="citation book cs1">Oswald, James (2007). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=-rZX8-tgjrUC&pg=PA5"><i>Vauban Under Siege: Engineering Efficiency and Martial Vigor in the War of the Spanish Succession</i></a>. Leiden, The Netherlands: Koninklijke Brill. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-90-04-15489-6" title="Special:BookSources/978-90-04-15489-6"><bdi>978-90-04-15489-6</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Vauban+Under+Siege%3A+Engineering+Efficiency+and+Martial+Vigor+in+the+War+of+the+Spanish+Succession&rft.place=Leiden%2C+The+Netherlands&rft.pub=Koninklijke+Brill&rft.date=2007&rft.isbn=978-90-04-15489-6&rft.aulast=Oswald&rft.aufirst=James&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D-rZX8-tgjrUC%26pg%3DPA5&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation book cs1"><a rel="nofollow" class="external text" href="https://babel.hathitrust.org/cgi/pt?id=njp.32101075691319;view=2up;seq=244"><i>Text Book of Fortification and Military Engineering, Part II: Permanent Fortification.-Historical Development.-Siege Work.-Coast Defence</i></a>. London: <a href="/wiki/HMSO" class="mw-redirect" title="HMSO">HMSO</a> for Royal Military Academy, Woolwich. 1893. <a href="/wiki/OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/558530637">558530637</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Text+Book+of+Fortification+and+Military+Engineering%2C+Part+II%3A+Permanent+Fortification.-Historical+Development.-Siege+Work.-Coast+Defence&rft.place=London&rft.pub=HMSO+for+Royal+Military+Academy%2C+Woolwich&rft.date=1893&rft_id=info%3Aoclcnum%2F558530637&rft_id=https%3A%2F%2Fbabel.hathitrust.org%2Fcgi%2Fpt%3Fid%3Dnjp.32101075691319%3Bview%3D2up%3Bseq%3D244&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSpiteri2012" class="citation journal cs1"><a href="/wiki/Stephen_C._Spiteri" title="Stephen C. Spiteri">Spiteri, Stephen C.</a> (January 2012). <a rel="nofollow" class="external text" href="https://issuu.com/arkitettura/docs/forttigne">"ARX Occasional Papers - Fort Tigné - 1792"</a>. <i>Arx - International Journal of Military Architecture and Fortification</i> (1)<span class="reference-accessdate">. Retrieved <span class="nowrap">3 February</span> 2019</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Arx+-+International+Journal+of+Military+Architecture+and+Fortification&rft.atitle=ARX+Occasional+Papers+-+Fort+Tign%C3%A9+-+1792&rft.issue=1&rft.date=2012-01&rft.aulast=Spiteri&rft.aufirst=Stephen+C.&rft_id=https%3A%2F%2Fissuu.com%2Farkitettura%2Fdocs%2Fforttigne&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWade2011" class="citation book cs1">Wade, Arthur P. (2011). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=Py7DBgAAQBAJ&pg=PA111"><i>Artillerists and Engineers</i></a>. McLean VA: Coast Defense Study Group (CDSG) Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-9748167-2-2" title="Special:BookSources/978-0-9748167-2-2"><bdi>978-0-9748167-2-2</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Artillerists+and+Engineers&rft.place=McLean+VA&rft.pub=Coast+Defense+Study+Group+%28CDSG%29+Press&rft.date=2011&rft.isbn=978-0-9748167-2-2&rft.aulast=Wade&rft.aufirst=Arthur+P.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DPy7DBgAAQBAJ%26pg%3DPA111&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWard1901" class="citation book cs1">Ward, Bernard Rowland (Major R. E.) (1901). <i>Notes on Fortification: With a Synoptical Chart</i>. London: John Murray. <a href="/wiki/OCLC_(identifier)" class="mw-redirect" title="OCLC (identifier)">OCLC</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/oclc/681477807">681477807</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Notes+on+Fortification%3A+With+a+Synoptical+Chart&rft.place=London&rft.pub=John+Murray&rft.date=1901&rft_id=info%3Aoclcnum%2F681477807&rft.aulast=Ward&rft.aufirst=Bernard+Rowland+%28Major+R.+E.%29&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFZaloga2012" class="citation book cs1">Zaloga, Steven J. (20 March 2012). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=2aG6CwAAQBAJ&pg=PA94"><i>Metz 1944: Patton's Fortified Nemesis</i></a>. Campaign, 242. Oxford: Osprey. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-84908-591-5" title="Special:BookSources/978-1-84908-591-5"><bdi>978-1-84908-591-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Metz+1944%3A+Patton%27s+Fortified+Nemesis&rft.place=Oxford&rft.series=Campaign%2C+242&rft.pub=Osprey&rft.date=2012-03-20&rft.isbn=978-1-84908-591-5&rft.aulast=Zaloga&rft.aufirst=Steven+J.&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D2aG6CwAAQBAJ%26pg%3DPA94&rfr_id=info%3Asid%2Fen.wikipedia.org%3APolygonal+fort" class="Z3988"></span></li></ul> <p><br /> </p> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist 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title="Circular rampart">Circular rampart</a></li> <li><a href="/wiki/City_gate" title="City gate">City gate</a></li> <li><a href="/wiki/Crannog" title="Crannog">Crannog</a></li> <li><a href="/wiki/Ditch_(fortification)" title="Ditch (fortification)">Ditch</a></li> <li><a href="/wiki/Defensive_wall" title="Defensive wall">Defensive wall</a></li> <li><a href="/wiki/Dun_(fortification)" title="Dun (fortification)">Dun</a></li> <li><a href="/wiki/Faussebraye" title="Faussebraye">Faussebraye</a></li> <li><a href="/wiki/Gatehouse" title="Gatehouse">Gatehouse</a></li> <li><a href="/wiki/Gord_(archaeology)" title="Gord (archaeology)">Gord</a></li> <li><a href="/wiki/Hillfort" title="Hillfort">Hillfort</a></li> <li><a href="/wiki/Landwehr_(border)" title="Landwehr (border)">Landwehr</a></li> <li><span title="Latin-language text"><i lang="la"><a href="/wiki/Limes_(Roman_Empire)" title="Limes (Roman Empire)">Limes</a></i></span></li> <li><a href="/wiki/Nuraghe" title="Nuraghe">Nuraghe</a></li> <li><span title="Latin-language text"><i lang="la"><a href="/wiki/Oppidum" title="Oppidum">Oppidum</a></i></span></li> <li><a href="/wiki/Palisade" title="Palisade">Palisade</a></li> <li><a href="/wiki/Pincer_gate" title="Pincer gate">Pincer gate</a></li> <li><a href="/wiki/Promontory_fort" title="Promontory fort">Promontory fort</a></li> <li><a href="/wiki/Rampart_(fortification)" title="Rampart (fortification)">Rampart</a></li> <li><a href="/wiki/Ringfort" title="Ringfort">Ringfort</a> (Rath)</li> <li><a href="/wiki/Refuge_castle" title="Refuge castle">Refuge castle</a></li> <li><span title="German-language text"><i lang="de"><a href="/wiki/Schwedenschanze" title="Schwedenschanze">Schwedenschanze</a></i></span></li> <li><a href="/wiki/Stockade" title="Stockade">Stockade</a></li> <li><span title="Latin-language text"><i lang="la"><a href="/wiki/Sudis_(stake)" title="Sudis (stake)">Sudis</a></i></span></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Trou_de_loup" title="Trou de loup">Trou de loup</a></i></span></li> <li><span title="Latin-language text"><i lang="la"><a href="/wiki/Vallum" title="Vallum">Vallum</a></i></span></li> <li><a href="/wiki/Wagon_fort" title="Wagon fort">Wagon fort</a> (<span title="Afrikaans-language text"><i lang="af">Laager</i></span>)</li> <li><a href="/wiki/Vitrified_fort" title="Vitrified fort">Vitrified fort</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Medieval_fortification" title="Medieval fortification">Post-classical</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Advanced_work" title="Advanced work">Advanced work</a></li> <li><a href="/wiki/Albarrana_tower" title="Albarrana tower">Albarrana tower</a></li> <li><a href="/wiki/Alcazaba" class="mw-redirect" title="Alcazaba">Alcazaba</a></li> <li><span title="Spanish-language text"><i lang="es"><a href="/wiki/Alc%C3%A1zar" title="Alcázar">Alcázar</a></i></span></li> <li><a href="/wiki/Amba_(landform)" title="Amba (landform)">Amba</a></li> <li><a href="/wiki/Arrowslit" title="Arrowslit">Arrowslit</a></li> <li><a href="/wiki/Barbican" title="Barbican">Barbican</a></li> <li><a href="/wiki/Bartizan" title="Bartizan">Bartizan</a></li> <li><a href="/wiki/Bastion" title="Bastion">Bastion</a></li> <li><a href="/wiki/Battery_tower" title="Battery tower">Battery tower</a></li> <li><a href="/wiki/Battlement" title="Battlement">Battlement</a></li> <li><a href="/wiki/Bawn" title="Bawn">Bawn</a></li> <li><a href="/wiki/Bent_entrance" title="Bent entrance">Bent entrance</a></li> <li><span title="German-language text"><i lang="de"><a href="/wiki/Bergfried" title="Bergfried">Bergfried</a></i></span></li> <li><span title="German-language text"><i lang="de"><a href="/wiki/Berm" title="Berm">Berm</a></i></span></li> <li><a href="/wiki/Boom_(navigational_barrier)" title="Boom (navigational barrier)">Boom</a></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Bret%C3%A8che" title="Bretèche">Bretèche</a></i></span></li> <li><a href="/wiki/Bridge_castle" title="Bridge castle">Bridge castle</a></li> <li><a href="/wiki/Bridge_tower" title="Bridge tower">Bridge tower</a></li> <li><a href="/wiki/Burh" title="Burh">Burh</a></li> <li><a href="/wiki/Butter-churn_tower" title="Butter-churn tower">Butter-churn tower</a></li> <li><a href="/wiki/Caer" title="Caer">Caer</a></li> <li><a href="/wiki/Caltrop" title="Caltrop">Caltrop</a></li> <li><a href="/wiki/Castle" title="Castle">Castle</a></li> <li><a href="/wiki/Chamber_gate" title="Chamber gate">Chamber gate</a></li> <li><a href="/wiki/Chartaque" title="Chartaque">Chartaque</a></li> <li><span title="Japanese-language text"><i lang="ja-Latn"><a href="/wiki/Chashi" title="Chashi">Chashi</a></i></span></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Chemin_de_ronde" title="Chemin de ronde">Chemin de ronde</a></i></span></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Chemise_(wall)" title="Chemise (wall)">Chemise</a></i></span></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Cheval_de_frise" title="Cheval de frise">Cheval de frise</a></i></span></li> <li><a href="/wiki/Citadel" title="Citadel">Citadel</a></li> <li><a href="/wiki/Coercion_castle" title="Coercion castle">Coercion castle</a></li> <li><a href="/wiki/Concentric_castle" title="Concentric castle">Concentric castle</a></li> <li><a href="/wiki/Corner_tower" title="Corner tower">Corner tower</a></li> <li><a href="/wiki/Counter-castle" title="Counter-castle">Counter-castle</a></li> <li><a href="/wiki/Curtain_wall_(fortification)" title="Curtain wall (fortification)">Curtain</a></li> <li><a href="/wiki/Drawbridge" title="Drawbridge">Drawbridge</a></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Enceinte" title="Enceinte">Enceinte</a></i></span></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Embrasure" title="Embrasure">Embrasure</a></i></span></li> <li><a href="/wiki/Flanking_tower" title="Flanking tower">Flanking tower</a></li> <li>Fortified buildings (<a href="/wiki/Fortified_church" title="Fortified church">church</a>, <a href="/wiki/Fortified_house" title="Fortified house">house</a>, <a href="/wiki/Dzong_architecture" title="Dzong architecture">Dzong</a>)</li> <li><a href="/wiki/Fujian_tulou" title="Fujian tulou">Fujian tulou</a></li> <li><i><a href="/wiki/Ganerbenburg" title="Ganerbenburg">Ganerbenburg</a></i></li> <li><a href="/wiki/Gate_tower" title="Gate tower">Gate tower</a></li> <li><a href="/wiki/Gabion" title="Gabion">Gabion</a></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Glacis" title="Glacis">Glacis</a></i></span></li> <li><a href="/wiki/Guard_tower" title="Guard tower">Guard tower</a></li> <li><span title="Russian-language text"><i lang="ru-Latn"><a href="/wiki/Gulyay-gorod" title="Gulyay-gorod">Gulyay-gorod</a></i></span></li> <li><span title="Japanese-language text"><i lang="ja-Latn"><a href="/wiki/Gusuku" title="Gusuku">Gusuku</a></i></span></li> <li><a href="/wiki/Half_tower" title="Half tower">Half tower</a></li> <li><a href="/wiki/Hoarding_(castle)" title="Hoarding (castle)">Hoarding</a></li> <li><a href="/wiki/Inner_bailey" title="Inner bailey">Inner bailey</a></li> <li><a href="/wiki/Kasbah" title="Kasbah">Kasbah</a></li> <li><a href="/wiki/Keep" title="Keep">Keep</a></li> <li><span title="Russian-language text"><i lang="ru-Latn"><a href="/wiki/Kremlin_(fortification)" title="Kremlin (fortification)">Kremlin</a></i></span> <small>(<span title="Russian-language text"><i lang="ru-Latn"><a href="/wiki/Detinets" title="Detinets">Detinets</a></i></span>)</small></li> <li><a href="/wiki/Ksar" title="Ksar">Ksar</a></li> <li><span title="German-language text"><i lang="de"><a href="/wiki/Landesburg" title="Landesburg">Landesburg</a></i></span></li> <li><a href="/wiki/L-plan_castle" title="L-plan castle">L-plan castle</a></li> <li><a href="/wiki/Machicolation" title="Machicolation">Machicolation</a></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Merlon" title="Merlon">Merlon</a></i></span></li> <li><a href="/wiki/Moat" title="Moat">Moat</a></li> <li><a href="/wiki/Motte-and-bailey_castle" title="Motte-and-bailey castle">Motte-and-bailey</a></li> <li><a href="/wiki/Murder_hole" title="Murder hole">Murder hole</a></li> <li><a href="/wiki/Neck_ditch" title="Neck ditch">Neck ditch</a></li> <li><a href="/wiki/Outer_bailey" title="Outer bailey">Outer bailey</a></li> <li><a href="/wiki/Outwork" title="Outwork">Outwork</a></li> <li><a href="/wiki/Peel_tower" title="Peel tower">Peel tower</a></li> <li><a href="/wiki/Portcullis" title="Portcullis">Portcullis</a></li> <li><a href="/wiki/Postern" title="Postern">Postern</a></li> <li><a href="/wiki/Powder_tower" title="Powder tower">Powder tower</a></li> <li><a href="/wiki/Qalat_(fortress)" title="Qalat (fortress)">Qalat</a></li> <li><a href="/wiki/Reduit" title="Reduit">Reduit</a></li> <li><a href="/wiki/Ribat" title="Ribat">Ribat</a></li> <li><a href="/wiki/Ricetto" title="Ricetto">Ricetto</a></li> <li><a href="/wiki/Ringwork" title="Ringwork">Ringwork</a></li> <li><a href="/wiki/Roundel_(fortification)" title="Roundel (fortification)">Roundel</a></li> <li><a href="/wiki/Quadrangular_castle" title="Quadrangular castle">Quadrangular castle</a></li> <li><a href="/wiki/Shell_keep" title="Shell keep">Shell keep</a></li> <li><a href="/wiki/Shield_wall_(castle)" title="Shield wall (castle)">Shield wall</a></li> <li><span title="Japanese-language text"><i lang="ja-Latn"><a href="/wiki/Japanese_castle" title="Japanese castle">Shiro</a></i></span></li> <li><a href="/wiki/Toll_castle" title="Toll castle">Toll castle</a></li> <li><a href="/wiki/Tower_castle" title="Tower castle">Tower castle</a></li> <li><a href="/wiki/Tower_house" title="Tower house">Tower house</a></li> <li><a href="/wiki/Turret_(architecture)" title="Turret (architecture)">Turret</a></li> <li><a href="/wiki/Viking_ring_fortress" title="Viking ring fortress">Viking ring fortress</a></li> <li><a href="/wiki/Fortified_tower" title="Fortified tower">Wall tower</a></li> <li><a href="/wiki/Bailey_(castle)" title="Bailey (castle)">Bailey (or ward)</a></li> <li><a href="/wiki/Watchtower" title="Watchtower">Watchtower</a></li> <li><a href="/wiki/Witch_tower" title="Witch tower">Witch tower</a></li> <li><span title="Japanese-language text"><i lang="ja-Latn"><a href="/wiki/Yagura_(tower)" title="Yagura (tower)">Yagura</a></i></span></li> <li><a href="/wiki/Yett" title="Yett">Yett</a></li> <li><a href="/wiki/Zwinger" title="Zwinger">Zwinger</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Modern</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:3em">Early modern</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><span title="German-language text"><i lang="de"><a href="/wiki/Abwurfdach" class="mw-redirect" title="Abwurfdach">Abwurfdach</a></i></span></li> <li><a href="/wiki/Arsenal" title="Arsenal">Arsenal</a></li> <li><a href="/wiki/Barricade" title="Barricade">Barricade</a></li> <li><a href="/wiki/Bastion" title="Bastion">Bastion</a></li> <li><a href="/wiki/Blockhouse" title="Blockhouse">Blockhouse</a></li> <li><a href="/wiki/Breastwork_(fortification)" title="Breastwork (fortification)">Breastwork</a></li> <li><a href="/wiki/Canal" title="Canal">Canal</a></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Caponier" title="Caponier">Caponier</a></i></span></li> <li><a href="/wiki/Casemate" title="Casemate">Casemate</a></li> <li><a href="/wiki/Cavalier_(fortification)" title="Cavalier (fortification)">Cavalier</a></li> <li><a href="/wiki/Counterguard" title="Counterguard">Counterguard</a></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Couvreface" title="Couvreface">Couvreface</a></i></span></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Coupure" title="Coupure">Coupure</a></i></span></li> <li><a href="/wiki/Covertway" title="Covertway">Covertway</a></li> <li><a href="/wiki/Crownwork" title="Crownwork">Crownwork</a></li> <li><a href="/wiki/Device_Forts" title="Device Forts">Device Forts</a></li> <li><a href="/wiki/Entrenchment_(fortification)" title="Entrenchment (fortification)">Entrenchment</a></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Fl%C3%A8che_(fortification)" title="Flèche (fortification)">Flèche</a></i></span></li> <li><a href="/wiki/Gorge_(fortification)" title="Gorge (fortification)">Gorge</a></li> <li><a href="/wiki/Gunpowder_magazine" title="Gunpowder magazine">Gunpowder magazine</a></li> <li><a href="/wiki/Hornwork" title="Hornwork">Hornwork</a></li> <li><a href="/wiki/Kotta_mara" title="Kotta mara">Kotta mara</a></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Lunette_(fortification)" title="Lunette (fortification)">Lunette</a></i></span></li> <li><a href="/wiki/Magazine_(artillery)" title="Magazine (artillery)">Magazine</a></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Orillon" title="Orillon">Orillon</a></i></span></li> <li><span title="Russian-language text"><i lang="ru-Latn"><a href="/wiki/Ostrog_(fortress)" title="Ostrog (fortress)">Ostrog</a></i></span></li> <li><a href="/wiki/Palanka_(fortification)" title="Palanka (fortification)">Palanka</a></li> <li><a href="/wiki/Place-of-arms" title="Place-of-arms">Place-of-arms</a></li> <li><a class="mw-selflink selflink">Polygonal fort</a></li> <li><span title="Spanish-language text"><i lang="es"><a href="/wiki/Presidio" title="Presidio">Presidio</a></i></span> (Spanish America)</li> <li><a href="/wiki/Punji_stick" title="Punji stick">Punji sticks</a></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Ravelin" title="Ravelin">Ravelin</a></i></span></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Redan" title="Redan">Redan</a></i></span></li> <li><a href="/wiki/Redoubt" title="Redoubt">Redoubt</a></li> <li><a href="/wiki/Retrenchment_(military)" title="Retrenchment (military)">Retrenchment</a></li> <li><a href="/wiki/Sally_port" title="Sally port">Sally port</a></li> <li><a href="/wiki/Sandbag" title="Sandbag">Sandbag</a></li> <li><a href="/wiki/Counterscarp" title="Counterscarp">Scarp and Counterscarp</a></li> <li><a href="/wiki/Sconce_(fortification)" title="Sconce (fortification)">Sconce</a></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Schanze" title="Schanze">Schanze</a></i></span></li> <li><a href="/wiki/Sea_fort" class="mw-redirect" title="Sea fort">Sea fort</a></li> <li><a href="/wiki/Station_(frontier_defensive_structure)" title="Station (frontier defensive structure)">Station</a></li> <li><a href="/wiki/Star_fort" class="mw-redirect" title="Star fort">Star fort</a></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Tenaille" title="Tenaille">Tenaille</a></i></span></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:3em">19th century</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Barbed_wire" title="Barbed wire">Barbed wire</a></li> <li><span title="French-language text"><i lang="fr"><a href="/wiki/Barbette" title="Barbette">Barbette</a></i></span></li> <li><a href="/wiki/Border_outpost" title="Border outpost">Border outpost</a></li> <li><a href="/wiki/Bunker" title="Bunker">Bunker</a></li> <li><a href="/wiki/Coastal_artillery" title="Coastal artillery">Coastal artillery</a></li> <li><a href="/wiki/Disappearing_gun" title="Disappearing gun">Disappearing gun</a></li> <li><a href="/wiki/Fire_control_tower" title="Fire control tower">Fire control tower</a></li> <li><a href="/wiki/Gun_turret" title="Gun turret">Gun turret</a></li> <li><a href="/wiki/Land_mine" title="Land mine">Land mine</a></li> <li><a href="/wiki/Martello_tower" title="Martello tower">Martello tower</a></li> <li><a href="/wiki/Outpost_(military)" title="Outpost (military)">Outpost</a></li> <li><a class="mw-selflink selflink">Polygonal fort</a></li> <li><span title="Persian-language text"><i lang="fa-Latn"><a href="/wiki/Sangar_(fortification)" title="Sangar (fortification)">Sangar</a></i></span></li> <li><a href="/wiki/Wire_obstacle" title="Wire obstacle">Wire obstacles</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:3em">20th century</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Admiralty_scaffolding" title="Admiralty scaffolding">Admiralty scaffolding</a></li> <li><a href="/wiki/Air_raid_shelter" title="Air raid shelter">Air raid shelter</a></li> <li><a href="/wiki/Anti-tank_trench" title="Anti-tank trench">Anti-tank trench</a></li> <li><a href="/wiki/Barbed_tape" class="mw-redirect" title="Barbed tape">Barbed tape</a></li> <li><a href="/wiki/Cointet-element" title="Cointet-element">Belgian gate</a></li> <li><a href="/wiki/Blast_shelter" title="Blast shelter">Blast shelter</a></li> <li><a href="/wiki/Blast_wall" title="Blast wall">Blast wall</a></li> <li><a href="/wiki/Border_security" class="mw-redirect" title="Border security">Border security</a></li> <li><a href="/wiki/Bomb_shelter" title="Bomb shelter">Bomb shelter</a></li> <li><a href="/wiki/Buoy_anti-tank_obstacle" title="Buoy anti-tank obstacle">Buoy</a></li> <li><a href="/wiki/Bremer_wall" title="Bremer wall">Bremer wall</a></li> <li><a href="/wiki/Concertina_wire" title="Concertina wire">Concertina wire</a></li> <li><a href="/wiki/Defensive_fighting_position" title="Defensive fighting position">Defensive fighting position</a></li> <li><a href="/wiki/British_anti-invasion_preparations_of_the_Second_World_War#Lines_and_islands" title="British anti-invasion preparations of the Second World War">British "hedgehog" road block</a></li> <li><a href="/wiki/Czech_hedgehog" title="Czech hedgehog">Czech hedgehog</a></li> <li><a href="/wiki/Dragon%27s_teeth_(fortification)" title="Dragon's teeth (fortification)">Dragon's teeth</a></li> <li><a href="/wiki/Forward_operating_base" title="Forward operating base">Entry control point (ECP)</a></li> <li><a href="/wiki/Electric_fence" title="Electric fence">Electric fence</a></li> <li><a href="/wiki/Fallout_shelter" title="Fallout shelter">Fallout shelter</a></li> <li><a href="/wiki/Fire_support_base" title="Fire support base">Fire support base</a></li> <li><a href="/wiki/Flak_tower" title="Flak tower">Flak tower</a></li> <li><a href="/wiki/Hardened_aircraft_shelter" title="Hardened aircraft shelter">Hardened aircraft shelter</a></li> <li><a href="/wiki/Hesco_bastion" title="Hesco bastion">Hesco bastion</a></li> <li><a href="/wiki/Kabal_(earthworks)" title="Kabal (earthworks)">Kabal</a></li> <li><a href="/wiki/Loophole_(firearm)" title="Loophole (firearm)">Loophole</a></li> <li><a href="/wiki/Main_line_of_resistance" title="Main line of resistance">Main line of resistance</a></li> <li><a href="/wiki/Missile_launch_facility" title="Missile launch facility">Missile launch facility</a></li> <li><a href="/wiki/Pillbox_(military)" title="Pillbox (military)">Pillbox</a></li> <li><a href="/wiki/Revetment_(aircraft)" title="Revetment (aircraft)">Revetment</a></li> <li><a href="/wiki/Sentry_gun" title="Sentry gun">Sentry gun</a></li> <li><a href="/wiki/Spider_hole" title="Spider hole">Spider hole</a></li> <li><a href="/wiki/Submarine_pen" title="Submarine pen">Submarine pen</a></li> <li><a href="/wiki/Underground_hangar" title="Underground hangar">Underground hangar</a></li> <li><a href="/wiki/Weapon_storage_area" title="Weapon storage area">Weapon storage area</a></li> <li><a href="/wiki/Weapons_Storage_and_Security_System" title="Weapons Storage and Security System">Weapons Storage and Security System</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">By topography</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Cave_castle" title="Cave castle">Cave castle</a></li> <li><a href="/wiki/Hill_castle" title="Hill castle">Hill castle</a></li> <li><a href="/wiki/Hillfort" title="Hillfort">Hillfort</a></li> <li><a href="/wiki/Hillside_castle" title="Hillside castle">Hillside castle</a></li> <li><a href="/wiki/Hilltop_castle" title="Hilltop castle">Hilltop castle</a></li> <li><a href="/wiki/Island_castle" title="Island castle">Island castle</a></li> <li><a href="/wiki/Lowland_castle" title="Lowland castle">Lowland castle</a></li> <li><a href="/wiki/Marsh_castle" title="Marsh castle">Marsh castle</a></li> <li><a href="/wiki/Water_castle" title="Water castle">Moated castle</a></li> <li><a href="/wiki/Promontory_fort" title="Promontory fort">Promontory fort</a></li> <li><a href="/wiki/Ridge_castle" title="Ridge castle">Ridge castle</a></li> <li><span title="Italian-language text"><i lang="it"><a href="/wiki/Rocca_(fortification)" title="Rocca (fortification)">Rocca</a></i></span></li> <li><a href="/wiki/Rock_castle" title="Rock castle">Rock castle</a></li> <li><a href="/wiki/Spur_castle" title="Spur castle">Spur castle</a></li> <li><a href="/wiki/Water_castle" title="Water castle">Water castle</a></li> <li><a href="/wiki/Kotta_mara" title="Kotta mara">Floating water castle</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">By role</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Border_barrier" title="Border barrier">Border barrier</a></li> <li><a href="/wiki/Coastal_defence_and_fortification" title="Coastal defence and fortification">Coastal defence</a></li> <li><a href="/wiki/Coercion_castle" title="Coercion castle">Coercion castle</a></li> <li><a href="/wiki/Counter-castle" title="Counter-castle">Counter-castle</a></li> <li><a href="/wiki/Fence" title="Fence">Fence</a></li> <li><i><a href="/wiki/Ganerbenburg" title="Ganerbenburg">Ganerbenburg</a></i></li> <li><a href="/wiki/Jagdschloss" title="Jagdschloss">Hunting lodge</a></li> <li><a href="/wiki/Imperial_castle" title="Imperial castle">Imperial castle</a></li> <li><span title="German-language text"><i lang="de"><a href="/wiki/Kaiserpfalz" title="Kaiserpfalz">Kaiserpfalz</a></i></span></li> <li><span title="German-language text"><i lang="de"><a href="/wiki/Landesburg" title="Landesburg">Landesburg</a></i></span></li> <li><span title="German-language text"><i lang="de"><a href="/wiki/Lustschloss" title="Lustschloss">Lustschloss</a></i></span></li> <li><a href="/wiki/Military_base" title="Military base">Military base</a></li> <li><a href="/wiki/Obstacle" title="Obstacle">Obstacle</a></li> <li><span title="German-language text"><i lang="de"><a href="/wiki/Ordensburg" title="Ordensburg">Ordensburg</a></i></span></li> <li><a href="/wiki/Refuge_castle" title="Refuge castle">Refuge castle</a></li> <li><a href="/wiki/Toll_castle" title="Toll castle">Toll castle</a></li> <li><a href="/wiki/Urban_castle" title="Urban castle">Urban castle</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">By design</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Bastion_fort" title="Bastion fort">Bastion fort</a></li> <li><a href="/wiki/Bridge_castle" title="Bridge castle">Bridge castle</a></li> <li><a href="/wiki/Circular_rampart" title="Circular rampart">Circular rampart</a></li> <li><a href="/wiki/Concentric_castle" title="Concentric castle">Concentric castle</a></li> <li><a href="/wiki/L-plan_castle" title="L-plan castle">L-plan castle</a></li> <li><a href="/wiki/Motte-and-bailey_castle" title="Motte-and-bailey castle">Motte-and-bailey castle</a></li> <li><a href="/wiki/Quadrangular_castle" title="Quadrangular castle">Quadrangular castle</a></li> <li><a href="/wiki/Ringfort" title="Ringfort">Ringfort</a></li> <li><a href="/wiki/Ringwork" title="Ringwork">Ringwork</a></li> <li><a href="/wiki/Tower_castle" title="Tower castle">Tower castle</a></li> <li><a href="/wiki/Z-plan_castle" title="Z-plan castle">Z-plan castle</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Lists</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/List_of_bastion_forts" title="List of bastion forts">Bastion forts</a></li> <li><a href="/wiki/List_of_castles" title="List of castles">Castles</a></li> <li><a href="/wiki/List_of_cities_with_defensive_walls" title="List of cities with defensive walls">Cities with defensive walls</a></li> <li><a href="/wiki/Defense_line" title="Defense line">Defense line</a></li> <li><a href="/wiki/Fortified_estate" class="mw-redirect" title="Fortified estate">Fortified estate</a></li> <li><a href="/wiki/List_of_fortifications" title="List of fortifications">Fortifications</a></li> <li><a href="/wiki/List_of_forts" title="List of forts">Forts</a></li> <li><a href="/wiki/Lists_of_military_installations" title="Lists of military installations">Military installations</a></li> <li><a href="/wiki/List_of_walls" title="List of walls">Walls</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Related word</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Castle_town" title="Castle town">Castle town</a></li> <li><a href="/wiki/Ch%C3%A2teau" title="Château">Château</a></li> <li><a href="/wiki/Dungeon" title="Dungeon">Dungeon</a></li> <li><a href="/wiki/Festung" title="Festung">Festung</a></li> <li><a href="/wiki/Fortified_gateway" title="Fortified gateway">Fortified gateway</a></li> <li><a href="/wiki/Gatekeeper" title="Gatekeeper">Gatekeeper</a></li> <li><a href="/wiki/Loophole_(firearm)" title="Loophole (firearm)">Loophole</a></li> <li><a href="/wiki/National_redoubt" title="National redoubt">National redoubt</a></li> <li><a href="/wiki/Palas" title="Palas">Palas</a></li> <li><a href="/wiki/Picket_(military)" title="Picket (military)">Picket</a></li> <li><a href="/wiki/Schloss" title="Schloss">Schloss</a></li> <li><a href="/wiki/Trench" title="Trench">Trench</a></li> <li><a href="/wiki/Vedette_(sentry)" title="Vedette (sentry)">Vedette</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Other topics</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Civil_defense" title="Civil defense">Civil defense</a></li> <li><a href="/wiki/Continuity_of_government" title="Continuity of government">Continuity of government</a></li> <li><a href="/wiki/Military_urbanism" title="Military urbanism">Military urbanism</a></li> <li><a href="/wiki/Subterranean_warfare" title="Subterranean warfare">Subterranean warfare</a></li> <li><a href="/wiki/Siege" title="Siege">Siege</a></li> <li><a href="/wiki/Siege_engine" title="Siege engine">Siege engine</a> <ul><li><a href="/wiki/List_of_siege_engines" title="List of siege engines">list</a></li></ul></li> <li><a href="/wiki/Tunnel_warfare" title="Tunnel warfare">Tunnel warfare</a></li> <li><a href="/wiki/Trench_warfare" title="Trench warfare">Trench warfare</a></li> <li><a href="/wiki/Urban_warfare" title="Urban warfare">Urban warfare</a> <ul><li><a href="/wiki/Urban_guerrilla_warfare" class="mw-redirect" title="Urban guerrilla warfare">Guerrilla</a></li></ul></li></ul> </div></td></tr><tr><td class="navbox-abovebelow hlist" colspan="2"><div> <ul><li><span class="nobold">See also</span>: <b><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" 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