Defensive fighting positionA defensive fighting position (DFP) is a type of earthwork constructed in a military context, generally large enough to accommodate anything from one soldier to a fire team (or similar sized unit). Tobruk type positions are named after the system of defensive positions constructed, initially, by the Italian Army at Tobruk, Libya. After Tobruk fell to the Allies in January 1941, the existing positions were modified and significantly expanded by the Australian Army which, along with other Allied forces, reused them in the Siege of Tobruk.
Adrian helmetThe Adrian helmet (Casque Adrian) was an influential design of combat helmet originally produced for the French Army during World War I. Its original version, the M15, was the first standard helmet of the French Army and was designed when millions of French troops were engaged in trench warfare, and head wounds from the falling shrapnel generated by indirect fire became a frequent cause of battlefield casualties. Introduced in 1915, it was the first modern steel helmet and it served as the basic helmet of many armies well into the 1930s.
Investment (military)Investment is the military process of surrounding an enemy fort (or town) with armed forces to prevent entry or escape. It serves both to cut communications with the outside world and to prevent supplies and reinforcements from being introduced. A contravallation is a line of fortifications, built by the attackers around the besieged fortification facing towards an enemy fort to protect the besiegers from sorties by its defenders and to enhance the blockade.
Screw picketA screw picket is a metal device which is used to secure objects to the ground. Today, screw pickets are used widely to temporarily "picket" dogs. They are also used to graze animals such as sheep, goats, and horses. Screw pickets are also used to stabilize small trees, tent poles, and other objects that are intended to remain upright. The original picket was a stake hammered into the ground to secure a horse by tying it to the stake. This required a second tool (a hammer) or the availability of a rock to use instead of a tool.
SappingSapping is a term used in siege operations to describe the digging of a covered trench (a "sap") to approach a besieged place without danger from the enemy's fire. The purpose of the sap is usually to advance a besieging army's position towards an attacked fortification. It is excavated by specialised military units, whose members are often called sappers. By using the sap, the besiegers could move closer to the walls of a fortress, without exposing the sappers to direct fire from the defending force.
Underground livingUnderground living refers to living below the ground's surface, whether in natural or manmade caves or structures. Underground dwellings are an alternative to above-ground dwellings for some home seekers, including those who are looking to minimize impact on the environment. Factories and office buildings can benefit from underground facilities for many of the same reasons as underground dwellings such as noise abatement, energy use, and security.
RedoubtA redoubt (historically redout) is a fort or fort system usually consisting of an enclosed defensive emplacement outside a larger fort, usually relying on earthworks, although some are constructed of stone or brick. It is meant to protect soldiers outside the main defensive line and can be a permanent structure or a hastily constructed temporary fortification. The word means "a place of retreat".
Enfilade and defiladeEnfilade and defilade are concepts in military tactics used to describe a military formation's exposure to enemy fire. A formation or position is "in enfilade" if weapon fire can be directed along its longest axis. A unit or position is "in defilade" if it uses natural or artificial obstacles to shield or conceal itself from enfilade and hostile fire. The strategies, named by the English during the Hundred Years' War, use the French ("to put on a string or sling") and ("to slip away or off") spoken by English nobility of the time.
MinenwerferMinenwerfer ("mine launcher" or "mine thrower") is the German name for a class of short range mine shell launching mortars used extensively during the First World War by the Imperial German Army. The weapons were intended to be used by engineers to clear obstacles including bunkers and barbed wire, that longer range artillery would not be able to target accurately. The Germans studied the Siege of Port Arthur, where heavy artillery had been unable to destroy defensive structures like barbed wire and bunkers.
Brodie helmetThe Brodie helmet is a steel combat helmet designed and patented in London in 1915 by Latvian inventor John Leopold Brodie (Leopolds Janno Braude). A modified form of it became the Helmet, Steel, Mark I in Britain and the M1917 Helmet in the US. Colloquially, it was called the shrapnel helmet, battle bowler, Tommy helmet, tin hat, and in the United States the doughboy helmet. It was also known as the dishpan hat, tin pan hat, washbasin and Kelly helmet. The German Army called it the Salatschüssel (salad bowl).
