Friday, August 7, 2009


Flak towers (German: Flaktürme) were large, above-ground anti-aircraft gun blockhouses used by the Luftwaffe to defend against Allied air raids on certain cities during World War II. They also served as air-raid shelters for tens of thousands of people and to coordinate air defence.

Flak Tower, Vienna, Austria

After the first RAF raid on Berlin in 1940, Adolf Hitler ordered the construction of 3 massive flak towers to defend the capital from air attack. This massive project was completed in a mere 6 months. The priority of the project was evidenced in the fact that the German national rail schedule was altered in order to facilitate the shipment of the necessary materials, namely concrete, steel and lumber to the construction sites.

The flak towers were considered to be invulnerable to attack with the usual ordnance carried by Allied bombers. Constructed with concrete walls up to 3.5 metres thick, each flak tower was supported by a radar dish (retractable behind a thick concrete and steel dome in order to prevent damage during an air raid).

Although Allied aircraft generally appeared to have avoided the flak towers, it is unlikely the towers themselves would have withstood Grand Slam bombs which successfully penetrated much thicker reinforced concrete. The towers were able to sustain a rate of fire of 8000 rounds per minute from their multi-level guns, with a range of up to 14 km in a full 360-degree field of fire. The 3 flak towers around the outskirts of Berlin created a triangle of formidable anti-aircraft fire that covered the center of Berlin.

The flak towers had also been designed with the idea of using the above-ground bunkers as a civilian shelter, with room for 10,000 civilians, and even a hospital ward, inside. The towers, during the fall of Berlin, formed their own communities, with up to 30,000 or more Berliners taking refuge in a single tower during the battle. These towers were some of the safest places in the fought-over city and some of the last places to surrender to Allied forces, eventually forced to capitulate as supplies ran out.

The Soviets, in their assault on Berlin, found it difficult to inflict significant damage on the flak towers, even with some of the largest Soviet guns, such as the 203 mm howitzers. Soviet forces generally manoeuvered around the towers, and eventually sent in envoys to seek their submission. Unlike much of Berlin, the towers tended to be fully stocked with ammunition and supplies, and the gunners even used their anti-aircraft 20 mm cannons to defend against assault by ground units. The Zoo Tower was one of the last points of defence, with German armoured units rallying near it at Tiergarten, before trying to break out of the encircling Soviet Red Army.

For a time after the war, the conversion to representative objects with decorated facades was planned. After the war was lost, the demolition of the towers was in most cases unfeasible and many remain to this day.

Flak Tower Design Iterations

Each flak tower complex consisted of:

o a G-Tower (German: Gefechtsturm) or Combat Tower, also known as the Gun Tower, Battery Tower or Large Flak Tower, and

o an L-Tower (German: Leitturm) or Lead Tower also known as the Fire-control tower, command tower, listening bunker or small flak tower.

Flakturm I - Berliner Zoo, Berlin (1st Generation) G-Tower was demolished by the British at the end of the war. L-Tower was demolished after the war.

Flakturm II, G- Tower - Friedrichshain, Berlin (1st Generation)
G-Tower was partially demolished after the war; one side remains visible. L-Tower was demolished after the war.

Flakturm III - Humboldthain, Berlin (1st Generation) G-Tower was partially demolished after the war; one side remains visible. The interior can be visited. L-Tower was partially demolished after the war; some walls remain visible.

Flakturm IV - Heiligengeistfeld, Hamburg (1st Generation): G-Tower was transformed into a nightclub with a music school and music shops. L-Tower was demolished after the war.

Flakturm V - Wilhelmsburg, Hamburg (2nd Generation)
G-Tower remains to this day, L-Tower was demolished after the war.

Flakturm VI - Stiftskaserne, Vienna (3rd Generation)
G-Tower is located within a military base of the Austrian Army.

L-Tower (in Esterhazypark) is used as an aquarium ("Haus des Meeres")

There is a climbing wall on the outside of Flakturm VI.

Flakturm VII - G-Tower & L-Tower - Augarten, Vienna (3rd Generation)

G-Tower remains empty. The entire north-east and half of the east machine gun platforms have been removed during 2007 including the connecting walkways due to deterioration. The tower itself has been reinforced with steel cables encircling the entire structure, 12 cables are located above the machine gun nests, 6 just below, and an additional 4 midway up the tower. The tower is home to thousands of pigeons which nest on every platform and opening. The west side of the structure is used as a cellular communications tower. L-Tower remains empty.

Flakturm VIII - Arenberg Park, Vienna (2nd Generation)

Flakturm VIII G Tower

Flakturm VIII L Tower

G-Tower is used as a storehouse for art. L-Tower remains empty.

I used to live up the hill from the Pragstattel Flakturm in Stuttgart Germany:

Here it is at night:


  1. This is an interesting site. I've been inside the Humbolthain Tower. The scale of this tower is staggering. It towers above the local landscape and the station at Gesundbrunnen. It must have looked even more formidable when the structure was free standing and not piled up with earth, as it was after the war.

    No wonder the Soviets went round them and did not make a serious effort to storm these towers. It would have been a tough task.

    Apparently there was a tunnel from Gesundbrunnen U Bahn to the tower, although I'm not sure of this still survives today.