Within the Blohm and Voss shipyard in Hamburg, Germany, there are several large underground bunkers which in their heyday would have protected thousands of workers during the allied air raids. Bismarck was built here but in the war, the shipyard was mostly used for U-boat construction and repair of warships / U-boats.
Notice the pockmarks from the WW2 air raids
Above Ground entrance with bomb resistant roof
Stairs down to entrance - note flood protection barriers which can be fitted
In use until late 1990's
Internal blast doors
Original washing facilities
Cold war era washing facilities