The largest free-standing bunker in Germany is in Bremen. Strictly speaking, the facility is a ruin of a German Navy submarine shipyard.
During the last two years of the war, civilian forced laborers, concentration camp inmates and prisoners of war were used here. Bunker construction was 90 percent completed - then the bombs fell. Part of the building was used by the Bundeswehr as a material depot from 1960 to 2010. In 2011 it was converted into a memorial, which was opened in 2015.