Twenty bunkers were part of the Berlin Wall’s border system.
The Berlin Wall was not simply a single concrete barrier. East German authorities built a layered frontier around West Berlin, combining walls, fences, patrol roads, signal systems, anti-vehicle trenches, lighting, watchtowers, dog runs and controlled strips of ground. The bunkers formed one component of this wider military border infrastructure.
The figure of 20 refers specifically to bunkers in the Berlin Wall system. It should not be confused with the much larger number of watchtowers: the final system included hundreds of observation towers, with figures commonly given as 302 around West Berlin. Nor does the bunker total describe every fortified position along the entire inner-German border.
Construction began on 13 August 1961, and the barrier was repeatedly upgraded. The best-known final version, introduced from the 1970s, used prefabricated concrete wall segments backed by a heavily controlled “death strip.” Unlike parts of the inner-German border, the Berlin Wall itself did not use extensive minefields or spring guns, but it remained a formidable and lethal escape barrier until the crossings opened in November 1989.