Flak Towers (German: Flaktürme) were large concrete bunkers, with anti-aircraft guns mounted on the roof. They were built during the World War II by the Germans, for the defence of strategically important areas by the Luftwaffe against Allied air raids. These massive reinforced concrete buildings functioned simultaneously as shelters for tens of thousands of people, hospitals and military headquarters; for industrial production, as barracks and lodgings for personnel and even for the storage of art treasures from museums.
The idea for the Flak Towers came after the RAF's raid on Berlim in 1940 when Adolf Hitler ordered the construction of 3 massive flak towers to defend the capital from air attack. Each one of these towers were supported by a radar installation that had a retractable radar dish (the dish was retracted behind a thick concrete and steel dome in order to prevent damage in an air raid).
Hitler took personal interest in and even made some sketches for the tower design and construction process. In order to have the towers constructed in Berlin as fast as possible and to allow the fast shipment of concrete, steel and timber to the construction sides, the national rail service schedule had to be changed. The construction of the 3 towers finished in only 6 months. The towers that had concrete walls up to 3,5 meters thick were considered to be invulnerable to the usually used bombs carried by the Allied bombers however, they would be probably destroyed with more powerful bombs but that never happened as aircraft generally appeared to have avoided the areas with flak towers.
The Flak Towers present in the outskirts of Berlin created a triangle of formidable anti-aircraft fire that covered the centre of Berlin. The multi-level guns present in the towers were able to sustain a rate of fire of 8000 rounds per minute with a range of up to 14 km all around the tower. Allied planes avoided the towers when possible, but bombing runs were made against them. Some took direct bomb hits, but no major damage was done. The towers are credited with preventing the firestorms that engulfed other German cities, since the bombers couldn't form into the necessary firestorm configurations under the intense anti-aircraft fire from the Flak towers.
The towers had also been designed with the idea to be used as bunkers for civilian shelter (with capacity for 10 thousand) and were self-contained with their own water reservoirs, food supplies and even a hospital ward. For instance, during the battle for Berlin, up to 30 thousand or more Berliners formed communities inside a single tower. The Flak Towers were some of the last places to surrender to the USSR forces only, eventually being forced to capitulate as supplies dwindled. An explanation for that is the fact that 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.
During the assault on Berlin, the soviets faced some difficulties to damage the towers, even with some of the largest Soviet guns such as the 203 mm howitzers. 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 towers were always built in pairs:
- a G-Tower (German: Gefechtsturm) or Combat Tower, also known as the Gun Tower, Battery Tower or Large Flak Tower, and
- a L-Tower (German: Leitturm) or Lead Tower also known as the Fire-control tower, command tower, listening bunker or small flak tower.
There were three generations of Flak Towers:
- G-Towers were 70.5 × 70.5 × 39 m (231x231x128 ft), usually armed with eight (four twin) 128 mm guns and numerous 37 mm and thirty-two (eight quad) 20 mm guns.
- L-Towers were 50 × 23 × 39 m (164x75x128 ft), usually armed with sixteen (four quad) 20 mm guns.
- G-Towers were 57 × 57 × 41.6 m (187x187x136 ft), usually armed with eight (four twin) 128 mm guns and sixteen (four quad) 20 mm guns.
- L-Towers were 50 × 23 × 44 m (164x75x144 ft), usually armed with forty (ten quad) 20 mm guns.
- G-Towers were 43 × 43 × 54 m (141x141x177 ft), usually armed with eight (four twin) 128 mm guns and thirty-two (eight quad) 20 mm guns.
The evaluation of even larger Battery Towers was commissioned by Adolf Hitler. These would have been three times the size and firepower of flak towers.
When the war ended, several flak towers had been built and there were plans for additional ones in other places:
|Flakturm I - Berliner Zoo, Berlin||1st||
G-Tower was demolished by the British at the end of the war.
L-Tower was demolished after the war.
|Flakturm II - Friedrichshain, Berlin||1st||
G-Tower was partially demolished after the war; one side remains visible.
L-Tower was demolished after the war.
Both towers were covered over and now appear to be natural hills in Volkspark Friedrichshain. The G-Tower, known as Mont Klamott (Rubble Mountain) in Berlin, was the inspiration for songs by singer-songwriter Wolf Biermann and the rock band Silly.
|Flakturm III - Humboldthain, Berlin||1st||
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||
G-Tower was transformed into a nightclub with a music school and music shops.
This tower, containing six levels below the rooftop, includes in its design, as part of its air-raid shelter, two identical spaces for protection against gas attacks, one on the first floor (above ground level) and the other on the second floor. Both in Tower 1, they are about 300 sq. m. (3,230 sq. ft.) in area, and have six windows (openings in the wall).
L-Tower was demolished after the war and replaced by a very similar looking building by T-Mobile.
|Flakturm V - Stiftskaserne, Vienna||3rd||
G-Tower's inside area is used by the Austrian Army.
L-Tower (in Esterhazypark) has been used as a public aquarium, the Haus des Meeres, since 1957.
|Flakturm VI - Wilhelmsburg, Hamburg||2nd||G-Tower remains to this day, L-Tower was demolished after the war.|
|Flakturm VII - Augarten, Vienna||3rd||
G-Tower remains empty. The entire north-east and half of the east 20 mm 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 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 tower suffered an internal explosion, and several floors near the top are missing on one side. The west side of the structure is also used as a cellular communications tower.
L-Tower remains empty. Its use as a computer storage facility or an open air cinema is being considered.
|Flakturm VIII - Arenberg Park, Vienna||2nd||
G-Tower is used as a storehouse for art.
L-Tower remains empty.
|City||Planned towers (not built)|
Tiergarten (2 towers)
Hasenheide (in Tempelhof)
Reichstag (unsuitable for construction)
|Bremen||Bremen Neustadt Contrescarpe (2 towers)|
|Munich||Munich Railroad Station (8 towers)|
|Vienna||Original plans were to place the three towers in Schmelz, Prater & Floridsdorf.|