The word Bunker comes from the English language which, in its original sense, referred to the coal deposit found on boats. With the passage of time in the German language, the concept came to be used to refer to the place that offers shelter against an attack. This last meaning is what is applied in Spanish to the word bunker. To refer to a type of refuge or fortification that is used for purely defensive purposes, it is used during wars to protect itself from bombing, either by planes or any other vehicle of war.
In general, these types of buildings are made with very resistant materials. They are usually installed underground or hidden to minimize the possibility of bomb impact.
Throughout history this type of fortification has been one of the most used in the field of war, and among many, there are some that stand out for their historical importance, an example of this is the Führerbunker, which was located under the city of Berlin and whose objective was to protect the high command of the government and the Nazi army during the clashes of the Second World War.
It should be noted that bunkers are almost exclusively used in the military field, however, there are occasions when they are used in the civilian or mixed field. For this reason bunkers are classified into different types, among the best known the following can be mentioned:
Ditch: is a type of small structure, usually made of covered concrete, partially buried in the ground and usually part of a system of ditches. This type of fortification offers better protection to the soldiers than the open trench and in addition to these they include protection against air attacks, not to mention they are of great help to protect the soldiers against the weather.
Forts: characterized by being excavated in guard posts, they have concrete spaces where soldiers can shoot with firearms.