After the Royal Air Force bombed Berlin on October 1940, Adolf Hitler ordered the construction of several flak towers to protect his cities against the allied air threat. The first three pairs of towers went up in Berlin in 1940, followed in 1941 by another two pairs in Hamburg and finally the three pairs in Vienna, which were constructed between December 1942 and January 1945. All sixteen flak towers were designed by German architect Friedrich Tamms, employing hundreds of forced laborers and war-prisoners from all over Europe.

The massive reinforced concrete structures were equipped with anti-aircraft guns ranging from 20 mm to 128 mm in size, that could fire 8,000 rounds per minute at enemy aircraft over 14 kilometers away. Also present were radar dishes that could be retracted behind a thick concrete and steel dome to protect them from damage in an air raid. The lower floors provided air raid shelters for civilians, with room for 10,000 civilians, and even a hospital ward, inside.

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