FLAK TOWERS: German Third Reich. 1940-1945. Large reinforced concrete structures designed to perform two key functions as military installations they coordinated antiaircraft artillery defense and served as antiaircraft artillery battery sites; as civilian installations they provided large scale air raid shelters of exceptional resistance to bombs.

Flak towers were designed and constructed in pairs, a G Tower (known as the gun tower, combat tower, battery tower, or large flak tower) and the L Tower (known as the command tower, listening bunker, or small flak tower) located typically 300 to 500 meters away.  Although tower size and design varied, footprints of a maximum of 70 by 70 meters were found in the square G Towers, with L towers smaller and rectangular in shape.  The exception was the sixteen sided third generation Vienna towers, finished in 1944.  Tower heights varied but were in the 30 to 45 meter range;  tower wall thickness was in the 2 to 2.5 meter range.

The air raid protection features of the towers varied from site to site, as did the capacity in terms of the number of persons who could be sheltered, although the figures reported must be regarded as generally approximate.  The Berlin Zoo tower also held a 95 bed hospital; those in Vienna have been reported as having as many as 800 hospital beds available. At Humboldthain, tower design allowed ambulances to unload inside the tower directly at the elevators.  In addition, other specialized storage facilities were available to protect national art treasures.  Towers had independent power generation capability and water supplies to permit continued operation when the surrounding utilities were damaged or destroyed.

A total of eight tower complexes were constructed at the order of Reichs Chancellor Hitler following the first Royal Air Force raid on Berlin on the night of 25 August 1940.  Although additional towers were planned, Table 1. summarizes those actually constructed:

Table 44-1.  German World War II Flak Tower Complexes

City Complexes G Tower L Tower
Berlin (original plan for eight tower complexes) Berlin Zoo (1)

Humboldthain (1)

Friedrichshain (1)

4 pairs of 128 mm cannon, 37 mm cannon, 20 mm cannon

Berlin Zoo design shelter capacity of 8,000 and is reported to have housed 30,000 - Humboldthain may have housed as many as 40,000

Wurzburg Giant radar, Mannheim radar, Command Device 40, Shot Indicator System 37, 20 mm cannon
Hamburg (three complexes planned) Flak Tower IV (Heiligengeistfeld) (1)

Wilhelmsburg (2)

4 pairs of 128 mm cannon, 37 mm cannon, 20 mm cannon

Tower IV design shelter capacity of 18,000 and is reported to have been capable of housing 50,000-60,000

Wurzburg Giant radar, Mannheim radar, Command Device 40, Shot Indicator System 37, 20 mm cannon
Vienna (six complexes planned) Arenberg Park (2)

Stiftskaserne (3)

Augarten (3)

4 pairs of 128 mm cannon

shelter capacity of 15,000

Wurzburg Giant radar, Mannheim radar, Command Device 40, Shot Indicator System 37
Bremen (one complex planned) no towers constructed    

Notes: Three generations of towers were constructed, incorporating design changes based on combat experience - these are identified by (1), (2), and (3).

Sources: Foedrowitz, Michael, The Flak Towers in Berlin, Hamburg and Vienna 1940-1950, Atglen, Pennsylvania, United States of America, Schiffer Military/Aviation History, 1998.

Entry 0244