The Zoo Flak Tower was equipped with 88MM Artillery Pieces, mounted on the roof, which served both as anti-tank and anti-aircraft guns, in addition to various other types of heavy guns.
Berlin Zoo Tower is near 130 feet and their walls were something insane like 8 feet of solid concrete! I remember reading that there was enough ammunition and supplies at any one time to sustain a year long siege. There were 8 guns on the top of each tower, some claims that they had both 105mm-150mm used. and also quick firing 37 and 20mm secondary weapons for low level attacks.
Various other types of automatic weapons were also fired from the Zoo Flak Tower windows which were protected by steel shutters.
The Zoo Flak Tower was completely bomb, artillery, and bullet proof, with thick concrete walls; and, was used as a safety bunker to protect civilians, over 15000+ Berliners at any time.
The Zoo Flak Tower had its own well, and generators, causing the installation to be self-sufficient in both running water and electricity.
I read that next to each tower was a Luftwaffe communication tower, controlling the orders for both the searchlight and flak crews around the city.
During the battle of Berlin, accurate fire from 88 mm guns two kilometres away on the Berlin Zoo flak tower caused severe casualties on the Soviets.
Realizing this, the soviets launched assaults against the Zoo Flak Tower, manned by the the 1. Flak Division, and 18. Panzergrenadier division.
1. Flak Division, and 18. Panzergrenadier division survived repeated attacks. Soviet tank shells damaged windows but could no penetrate the concrete, they also took extreme casualties against the German Flak weapons.
It was stated 30000 Berliners were in the bomb shelters of the Zoo Flak Towers, waiting for the Americans to arrive.
By the end of the war, the Zoo Tower was one of the few buildings in Berlin still controlled by the Germans. Under their zone, The British struggled to demolish the building, before finally succeeding in 1948.
pic 1 - you can see 2 destroyed JS2 at the front of the photo, with 2 flaks at the top of the tower.
