Photo © Tom Kirsch, opacity.us
As the threat of air attacks in Western Germany increased during World War II, many air raid shelters (Luftschutzbunker) were constructed to protect both military and civilians. Most have been imploded, buried, or flooded by groundwater; this particular bunker survives however, and its location is kept quite secret. The facility, which might stretch to near one kilometer, consisted mainly of galleries where people could seek protection.
A very unique feature of the system was that it had expanded from its original plan to become an underground hospital - a safe haven to treat the wounded as the allied planes unloaded their weapons from above. The construction was never completed, and in one section the concrete tunnels transform into the rough shape carved out so many years ago. Another section remains mostly buried in dirt, and the third area is partly flooded yet mostly traversable.
The area fell under heavy bombing attacks from the RAF (Royal Air Force) from 1941 through 1945, subsequently annihilating most of the city. During the 1970s, part of the system was used to test artillery fired from tanks in preparation for the Cold War. Today, the bunker lies in an abandoned parcel of land, and hidden very well from the public.