The white arrows, lines, characters and words LSK, NA, ZIVIL etc. indicate air raid shelters for the civilians. They were established in cellars of buildings and mostly connected underneath from one house to the other with an opening through the walls intended for the house occupants. Air raid shelters has been visited during air raids and bombings on the city.
The signs on the walls were primary made to make rescuers finding the survivors and buried people more easily and only secondarily for accidental passers-by around the street. During bombings not everyone was allowed to find refuge from the attack. In fact, according to the ideology of National Socialism, Jewish neighbours and houses in Jewish property were excluded from all precautions.
Air raid shelters were places of fear and hard life of the civilian people during the war. The white signs on the walls are memorials of past, memorials of the terrible war and of the totalitarian control of the National Socialism regime.