Description: Partially demolished Flak-tower located in a park in central Berlin, two corners are still remaining. The fortress is one of six Hitler sketched himself. Built by Italian and French workers in 1941-42, each complex could hold around 15,000 civilians.
Partially demolished by French forces in 1948-51, the debris is landscaped around the base of the towers, but not on the north side, because of the railway close-by. The structures are 40 m. high, and there are guided tours.
Information provided by McMaster:
The statistics concerning this structure are staggering. Built from reinforced concrete, 2.5m (12 ft) thick foundations, 2m (6.5 ft) thick outside walls, inside walls up to 1.5m (5 ft) thick. The top floor, the roof was 3.5m (12 ft) thick.
The Gefechtsturm or G-Turm (lit. "Battle Tower")
Built in 1941-2, alongside the S-Bahn line, by Italian and French workers. In 1948 - 51 the G-Turm was partially demolished and the two southerly gun platforms destroyed. 1.6 millon cubic meters of rubble was heaped up around base to form artificial hill and to enhance the park to plans by Garden and Building Department Leader Gunther Rieck. The work was carried out by local jobless people. Most of the rubble was pilled around the south, east and west sides, access being available. But as the tower is build in close proximity to the railway, to the north, dumping and pilling rubble was not done to any great depth. So the northern side is left partially exposed.
The northern face of the bunker is still visible. In the north of the park, and now known as "Humboldt-85 höhe" it overlooks the Hochstrasse and the Gesundbrunnen U-Bahn station.