Battle of BerlinThe 'Battle of Berlin, designated as the Berlin Strategic Offensive Operation by the Soviet Union, and also known as the Fall of Berlin', was one of the last major offensives of the European theatre of World War II. After the Vistula–Oder offensive of January–February 1945, the Red Army had temporarily halted on a line east of Berlin. On 9 March, Germany established its defence plan for the city with Operation Clausewitz. The first defensive preparations at the outskirts of Berlin were made on 20 March, under the newly appointed commander of Army Group Vistula, General Gotthard Heinrici.
Air raid shelterAir raid shelters are structures for the protection of non-combatants as well as combatants against enemy attacks from the air. They are similar to bunkers in many regards, although they are not designed to defend against ground attack (but many have been used as defensive structures in such situations). During World War II, many types of structures were used as air raid shelters, such as cellars, Hochbunkers (in Germany), basements, and underpasses. Bombing raids during World War I led the UK to build 80 specially adapted London Underground stations as shelters.
BlockhouseA blockhouse is a small fortification, usually consisting of one or more rooms with loopholes, allowing its defenders to fire in various directions. It is usually an isolated fort in the form of a single building, serving as a defensive strong point against any enemy that does not possess siege equipment or, in modern times, artillery, air force and cruise missiles. A fortification intended to resist these weapons is more likely to qualify as a fortress or a redoubt, or in modern times, be an underground bunker.
Anti-aircraft warfareAnti-aircraft warfare, counter-air, anti-air, AA guns, layered air defence or air defence forces is the battlespace response to aerial warfare, defined by NATO as "all measures designed to nullify or reduce the effectiveness of hostile air action". It includes surface based, subsurface (submarine launched), and air-based weapon systems, associated sensor systems, command and control arrangements, and passive measures (e.g. barrage balloons). It may be used to protect naval, ground, and air forces in any location.
CasemateA casemate is a fortified gun emplacement or armored structure from which guns are fired, in a fortification, warship, or armoured fighting vehicle. When referring to antiquity, the term "casemate wall" means a double city wall with the space between the walls separated into chambers, which could be filled up to better withstand battering rams in case of siege (see Antiquity: casemate wall). In its original early modern meaning, the term referred to a vaulted chamber in a fort, which may have been used for storage, accommodation, or artillery which could fire through an opening or embrasure.
Flak towerFlak towers (Flaktürme) were large, above-ground, anti-aircraft gun blockhouse towers constructed by Nazi Germany. There were 8 flak tower complexes in the cities of Berlin (three), Hamburg (two), and Vienna (three) from 1940 onwards. Other cities that used flak towers included Stuttgart and Frankfurt. Smaller single-purpose flak towers were built at key outlying German strongpoints, such as at Angers in France, and Heligoland in Germany. The towers were operated by the Luftwaffe to defend against Allied strategic air raids against these cities during World War II.
Trench warfareTrench warfare is the type of land warfare using occupied lines largely comprising military trenches, in which troops are well-protected from the enemy's small arms fire and are substantially sheltered from artillery. It became archetypically associated with World War I (1914–1918), when the Race to the Sea rapidly expanded trench use on the Western Front starting in September 1914. Trench warfare proliferated when a revolution in firepower was not matched by similar advances in mobility, resulting in a grueling form of warfare in which the defender held the advantage.
Pillbox (military)A pillbox is a type of blockhouse, or concrete dug-in guard-post, often camouflaged, normally equipped with loopholes through which defenders can fire weapons. It is in effect a trench firing step, hardened to protect against small-arms fire and grenades, and raised to improve the field of fire. The modern concrete pillbox originated on the Western Front of World War I, in the German Army in 1916. The origin of the term is disputed.
Thermobaric weaponA thermobaric weapon, also called an aerosol bomb, or a vacuum bomb, is a type of explosive that uses oxygen from the surrounding air to generate a high-temperature explosion. The fuel–air explosive is one of the best-known types of thermobaric weapons. Thermobaric weapons are almost 100% fuel and as a result are significantly more energetic than conventional explosives of equal weight. The fuel is often elemental. Many types of thermobaric weapons can be fitted to hand-held launchers, and can also be launched from airplanes.
Nuclear bunker busterA nuclear bunker buster, also known as an earth-penetrating weapon (EPW), is the nuclear equivalent of the conventional bunker buster. The non-nuclear component of the weapon is designed to penetrate soil, rock, or concrete to deliver a nuclear warhead to an underground target. These weapons would be used to destroy hardened, underground military bunkers or other below-ground facilities. An underground explosion releases a larger fraction of its energy into the ground, compared to a surface burst or air burst explosion at or above the surface, and so can destroy an underground target using a lower explosive yield.
