Flak tower


Flak towers were eight complexes of large, above-ground, anti-aircraft gun blockhouse towers constructed by Nazi Germany in the cities of Berlin, Hamburg, and Vienna from 1940 onwards. Other cities that used flak towers included Stuttgart and Frankfurt. Smaller single-purpose flak towers were built at key outlying German strongpoints, such as at Angers in France, Helgoland in Germany.
The towers were operated by the Luftwaffe to defend against Allied strategic air raids against these cities during World War II. They also served as air-raid shelters for tens of thousands of local civilians.

History and uses

After the RAF's raid on Berlin in 1940, Adolf Hitler ordered the construction of three massive flak towers to defend the capital from air attack. Each tower had a radar installation with a radar dish which could be retracted behind a thick concrete and steel dome for protection.
Hitler was interested in the design of the towers, and even made some sketches. They were constructed in six months. The priority of the project was such that the German national rail schedule was altered to facilitate the shipment of concrete, steel and timber to the construction sites.
With concrete walls up to thick, flak towers were considered by their designers to be invulnerable to attack by the standard ordnance carried by RAF heavy bombers at the time of their construction.
The towers were able to sustain a rate of fire of per minute from their multi-level guns, with a range of up to in a field of fire. However, only the FlaK 40 guns had effective range to defend against the RAF and USAAF heavy bombers. The three flak towers around the outskirts of Berlin created a triangle of anti-aircraft fire that covered the centre 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 and a hospital ward inside. During the Battle of Berlin, occupants formed their own communities, with up to taking refuge in one tower during the battle. These towers, much like the keeps of medieval castles, were some of the safest places in a fought-over city and so the flak towers were some of the last places to surrender to the Red Army, eventually being forced to capitulate as supplies dwindled.
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 M1931 howitzers. Soviet forces generally manoeuvred around the towers, and eventually sent in envoys to seek their surrender. Unlike much of Berlin, the towers tended to be fully stocked with ammunition and supplies, and the defenders used 2 cm Flak cannon 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.
After the war, the demolition of the towers was often considered not feasible and many remain to this day, with some having been converted for alternate use.

Design iterations

Each flak tower complex consisted of:
;Generation 1
The G-Towers were square and tall, usually armed with eight 12.8 cm FlaK 40 and numerous 37 mm Flak and 32 20mm Flakvierling guns.
L-Towers were, usually armed with four quadruple 20 mm guns.
;Generation 2
G-Towers were, usually armed with eight 128 mm guns and sixteen 20 mm guns.
L-Towers were, usually armed with forty 20 mm guns.
;Generation 3
The G-Towers were, usually armed with eight 128 mm guns and thirty-two 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.

Towers

Flakturm I – Berliner Zoo, Berlin

The tower built near the Berlin Zoo was the first generation type and covered the government district. It was also used as a repository from artefacts from the Berlin museum. The occupants surrendered to Soviets on 30 April 1945
In 1947 the British blew up the G-Tower on the second attempt with several tons of explosives.. The L-Tower was demolished first in July.

Flakturm II – Friedrichshain, Berlin

Both towers were covered over and now appear to be natural hills in Volkspark Friedrichshain. The G-Tower, known as Mont Klamott in Berlin, was the inspiration for songs by singer-songwriter Wolf Biermann and the rock band Silly.

Flakturm III – Humboldthain, Berlin

The third of the first generation flak towers was built at Humboldthain
The G-Tower was partially demolished after the war; one side remains visible. The interior can be visited.. The L-Tower was partially demolished after the war; some walls remain visible.
Image:Humboldthain.jpg|Flakturm III G-Tower

Flakturm IV – Heiligengeistfeld, Hamburg

The G-Tower was transformed into a nightclub with a music school and music shops. In October 2019, the NH Hotel Group announced plans to turn it into a luxury hotel, opening in 2021.
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 and the other on the second floor. Both in Tower 1, they are about 300 sq. m. in area, and have six windows.
The L-Tower was demolished after the war and replaced by a building owned by T-Mobile..

Flakturm VI – Wilhelmsburg, Hamburg

The tower at Wilhelmsburg is a 2nd generation type.
The G-Tower remains to this day,, the L-Tower was demolished after the war.

Flakturm V – Stiftskaserne, Vienna

Berlin