Abandoned WW2 bomb shelter in Bremen, Germany

This bomb shelter was constructed in 1939 as one of over 300 bunkers in the city and could house around 200 people. The text says "Only enter if anti air guns are firing or the air raid sirens are on! Unauthorized entry will be punished! Chief of Police!"

The ceiling would not withstand a direct hit, it was only protection against shrapnel and debris - but they included a gas lock based on the experience from WW1.

The luminous paint still fulfills its purpose 80 years after it was applied to the walls!

Fans with a handcrank were standard to ventilate the rooms.

To further shield against gas attacks they produced overpressure in the shelter and cleaned the air with filter units like this one on top of the fan.

All rooms were numbered and could house a limited number of people as noted on the wall, active ventilation tripled the number of admitted people in the shelter.

Everything still left here is part of Allied relief aid packages sent after the war - most inventory dates back to around 1946-1950.