Flak Towers were large concrete bunkers, with anti-aircraft guns mounted on the roof. They were built during the Second World War by the Germans, for the defence of strategically important areas. These massive reinforced concrete buildings functioned simultaneously as shelters, hospitals and military headquarters; for industrial production, as barracks and lodgings for personnel and even for the storage of art treasures from museums.

The walls of the bunkers were 2.5 metres thick and the ceilings 3.5 metres, meaning they could withstand hits from the majority of Allied bombs.

Flak towers were always built in pairs: the G-Tower which housed the guns and an L-Tower. The L-Tower's function was target detection and designation and it was equipped with several different radar installations and rangefinders.

In the picture to the right, which shows the towers in the Arenberg Park in Vienna, you can see the L-Tower on the left and the larger G-Tower to the right.

When the war ended, flak towers had been built in Hamburg, Berlin and Vienna and there were plans for additional towers in Berlin, Hamburg, Bremen and Munich.

There were three generations of flak towers, the first comprising the Zoo, Humboldthain and Friedrichshain towers in Berlin and the Heiligengeistfeld towers in Hamburg. The Wilhelmsburg tower in Hamburg and the Arenberg Park tower in Vienna were the second generation and the Stiftskasernen and Augarten towers in Vienna the third. The fire control tower was virtually identical everywhere.


This site has been translated by

Richard Armstrong


The L-Towers were also armed, usually with sixteen 20 mm guns

The size of the G-Towers was:

1st Generation - 70.5 × 70.5 × 39 m.

2nd Generation - 57 × 57 × 41.6 m.

3rd Generation - 43 × 43 × 54 m.

The size of the L-Towers was:

1st Generation - 50 x 23 x 39 m.

2 - 3rd Generation - 50 x 23 x 44 m.

1st Generation

2nd Generation

Heiligengeisrfield  - Hamburg

Wilhelmsborg  - Hamburg

Augarten - Wien

3rd Generation