page_title: Fortification
section_title: 20th and 21st centuries
hierarchical_section_title: Fortification / History / 20th and 21st centuries
caption_attribution_description: English: The Fort Campbell in Malta is a ruin. It is located in the north of Malta, near the town of Mellieha. You can use this images for free. But a link to the source: http://www.ploync.de/reisen/122-reisehighlights-auf-malta.html - I would be happy&#160;:)
context_page_description: A fortification is a military construction or building designed for the defense of territories in warfare, and is also used to solidify rule in a region during peacetime. The term is derived from the Latin fortis and facere.
  From very early history to modern times, defensive walls have often been necessary for cities to survive in an ever-changing world of invasion and conquest. Some settlements in the Indus Valley Civilization were the first small cities to be fortified. In ancient Greece, large stone walls had been built in Mycenaean Greece, such as the ancient site of Mycenae. A Greek phrourion was a fortified collection of buildings used as a military garrison, and is the equivalent of the Roman castellum or English fortress. These constructions mainly served the purpose of a watch tower, to guard certain roads, passes, and borders. Though smaller than a real fortress, they acted as a border guard rather than a real strongpoint to watch and maintain the border.
  The art of setting out a military camp or constructing a fortification traditionally has been called "castrametation" since the time of the Roman legions.
context_section_description: Steel-and-concrete fortifications were common during the 19th and early 20th centuries. However the advances in modern warfare since World War I have made large-scale fortifications obsolete in most situations. In the 1930s and 1940s, some fortifications were built with designs taking into consideration the new threat of aerial warfare, for example Fort Campbell in Malta. Despite this, only underground bunkers are still able to provide some protection in modern wars. Many historical fortifications were demolished during the modern age, but a considerable number survive as popular tourist destinations and prominent local landmarks today.
  The downfall of permanent fortifications had two causes:
  The ever-escalating power, speed, and reach of artillery and air power meant that almost any target that could be located could be destroyed, if sufficient force were massed against it. As such, the more resources a defender devoted to reinforcing a fortification, the more combat power that fortification justified being devoted to destroying it, if the fortification's destruction was demanded by an attacker's strategy. From World War II, bunker busters were used against fortifications. By 1950, nuclear weapons were capable of destroying entire cities, and produced dangerous radiation. This led to the creation of civilian nuclear air raid shelters.
  The second weakness of permanent fortification was its very permanency. Because of this it was often easier to go around a fortification and, with the rise of mobile warfare in the beginning of World War II, this became a viable offensive choice. When a defensive line was too extensive to be entirely bypassed, massive offensive might could be massed against one part of the line allowing a breakthrough, after which the rest of the line could be bypassed. Such was the fate of the many defensive lines built before and during World War II, such as the Siegfried Line, the Stalin Line and the Atlantic Wall. This was not the case with the Maginot Line; it was designed to force the Germans to invade other countries (Belgium or Switzerland) to go around it, and was successful in that sense.
  Instead field fortification rose to dominate defensive action. Unlike the trench warfare which dominated World War I, these defences were more temporary in nature. This was an advantage because since it was less extensive it formed a less obvious target for enemy force to be directed against.
  If sufficient power were massed against one point to penetrate it, the forces based there could be withdrawn and the line could be re-established relatively quickly. Instead of a supposedly impenetrable defensive line, such fortifications emphasized defence in depth, so that as defenders were forced to pull back or were overrun, the lines of defenders behind them could take over the defence.
  Because the mobile offensives practised by both sides usually focused on avoiding the strongest points of a defensive line, these defences were usually relatively thin and spread along the length of a line. The defence was usually not equally strong throughout however.
  The strength of the defensive line in an area varied according to how rapidly an attacking force could progress in the terrain that was being defended—both the terrain the defensive line was built on and the ground behind it that an attacker might hope to break out into. This was both for reasons of the strategic value of the ground, and its defensive value.
  This was possible because while offensive tactics were focused on mobility, so were defensive tactics. The dug in defences consisted primarily of infantry and antitank guns. Defending tanks and tank destroyers would be concentrated in mobile brigades behind the defensive line. If a major offensive was launched against a point in the line, mobile reinforcements would be sent to reinforce that part of the line that was in danger of failing.
  Thus the defensive line could be relatively thin because the bulk of the fighting power of the defenders was not concentrated in the line itself but rather in the mobile reserves. A 
caption: Gun emplacement in Fort Campbell, built in the 1930s. Due to the threat of aerial warfare, the buildings were placed at a distance from each other, making it difficult to find from the air.
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