The Zoo flak tower, (German: Flakturm Tiergarten, Tiergarten Flak Tower or commonly shortened to "Zoo Tower"), was a fortified flak tower that existed in Berlin from 1941 to 1947. It was one of several flak towers that protected Berlin from Allied bomber raids. Its primary role was as a gun platform to protect the government building district of Berlin, in addition the Hochbunker (blockhouse) was designed to be used as a civilian air-raid shelter. It also contained a hospital and a radio transmitter for use by the German leadership, and provided secure storage facilities for art treasures.
During the Battle of Berlin, it acted as a citadel and by depressing its large anti-aircraft artillery, its garrison was able to provide support for ground operations against the encroaching Soviet Red Army.
The Berlin flak towers (Flaktürme, singular Flakturm) were originally built as a response to an attack on Berlin by a relatively small force of British bombers. Hitler ordered the construction of these towers after the first bomber attack on Berlin by the RAF on 25 August 1940. Although only 95 RAF bombers constituted the attack force, this was a grave domestic political embarrassment to Adolf Hitler, and in particular Hermann Göring, who had said that Berlin would never be bombed. The Zoo tower was built close to the Berlin Zoo, hence the name, and is the most famous of the flak towers. It was the first one built and protected the government quarter in Berlin.
The Zoo tower was a first generation flak tower. Like all the flak towers, it had a main facility that housed the anti aircraft guns, the G building, and a smaller building that had sensory equipment, including radar. This was the smaller L building. The two were connected by a landline that was buried in the ground and protected.