The Wilhelmshaven World War II bombings by the Allies of World War II destroyed two thirds of the port's buildings. From spring 1943 until November 1943 slave labourers of the SS-Baubrigade II from the Neuengamme camp were transferred to Wilhelmshaven to clear up after air raids.
References
Bombing of Wilhelmshaven in World War II Wikipedia(Text) CC BY-SA