Bunker in the context of "Combat engineer"

A defense line or fortification line is a geographically recognizable line of troops and armament, fortified and set up to protect a high-value location or defend territory, which is an "area of defense".

A defense line may be based on natural difficult terrain features, such as rivers or marshes, mountain ranges, or coastlines; temporary field fortification works such as trenches; and/or more permanent fortifications such as fortresses and bunkers.

A charge is an offensive maneuver in battle in which combatants advance towards their enemy at their best speed in an attempt to engage in a decisive close combat. The charge is the dominant shock attack and has been the key tactic and decisive moment of many battles throughout history. Modern charges usually involve small groups of fireteams equipped with weapons with a high rate of fire and striking against individual defensive positions (such as a concertainer or bunker), instead of large groups of combatants charging another group or a fortified line.

A 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 or 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. However, a blockhouse may also refer to a room within a larger fortification, usually a battery or redoubt.

The Führerbunker (German pronunciation: [ˈfyːʁɐˌbʊŋkɐ] ) was an air raid shelter located near the Reich Chancellery in Berlin, Germany. It was part of a subterranean bunker complex constructed in two phases in 1936 and 1944. It was the last of the Führer Headquarters (Führerhauptquartiere) used by Adolf Hitler during World War II.

Hitler took up residence in the Führerbunker on 16 January 1945, and it became the centre of the Nazi regime until the last week of World War II in Europe. Hitler married Eva Braun there on 29 April 1945, less than 40 hours before they committed suicide.

The Royal Flying Corps (RFC) was the air arm of the British Army before and during the First World War until it merged with the Royal Naval Air Service on 1 April 1918 to form the Royal Air Force. During the early part of the war, the RFC supported the British Army by artillery co-operation and photographic reconnaissance. This work gradually led RFC pilots into aerial battles with German pilots and later in the war included the strafing of enemy infantry and emplacements, the bombing of German military airfields and later the strategic bombing of German industrial and transport facilities.

At the start of World War I the RFC, commanded by Brigadier-General Sir David Henderson, consisted of five squadrons – one observation balloon squadron (RFC No 1 Squadron) and four aeroplane squadrons. These were first used for aerial spotting on 13 September 1914 but only became efficient when they perfected the use of wireless communication at Aubers Ridge on 9 May 1915. Aerial photography was attempted during 1914, but again only became effective the next year. By 1918, photographic images could be taken from 15,000 feet and were interpreted by over 3,000 personnel. Parachutes were not available to pilots of heavier-than-air craft in the RFC – nor were they used by the RAF during the First World War – although the Calthrop Guardian Angel parachute (1916 model) was officially adopted just as the war ended. By this time parachutes had been used by balloonists for three years.

SAR-Lupe is Germany's first reconnaissance satellite system and is used for military purposes. SAR is an abbreviation for synthetic-aperture radar, and "Lupe" is German for magnifying glass. The SAR-Lupe program consists of five identical (770 kg) satellites, developed by the German aeronautics company OHB-System, which are controlled by a ground station responsible for controlling the system and analysing the retrieved data. A large data archive of images will be kept in a former Cold War bunker belonging to the Kommando Strategische Aufklärung (Strategic Reconnaissance Command) of the Bundeswehr. The total price of the satellites was over 250 million Euro.

In military tactics, a strongpoint is a key point in a defensive fighting position which anchors the overall defense line. This may include redoubts, bunkers, pillboxes, trenches or fortresses, alone or in combination; the primary requirement is that it should not be easily overrun or avoided. A blocking position in good defensive terrain commanding the lines of communication, such as high ground, is preferred. Examples from history include Thermopylae, where the ancient Greeks held back a much larger Persian army, and Monte Cassino, which anchored the Winter Line in Italy in World War II.