Starting in October 1940, the Nazis began to build military facilities known as flak bunkers or flak towers, first in Berlin and later in Hamburg and Vienna. They consisted of a Leitturm (lead tower) and a Geschützturm (gun tower) which had anti-aircraft guns known as Flug-Abwehr-Kanonen (flak guns) mounted on its roof. Hamburg had a much bigger flak bunker on Feldstrasse in St Pauli, which still exists, as well as one in Wilhelmsburg, which was afterwards built in 1943.
Most of the construction work in Wilhelmsburg was carried out by forced labourers and prisoners of war. Only a few floors of the flak towers were reserved as air-raid shelters for the population. Most people took shelter in civil defence bunkers and secured cellar rooms in the city’s residential areas. Forced labourers were not allowed to use the shelters.
After the war, in 1947, the British Army destroyed the interior of the building in a controlled explosion. Six of the eight floors collapsed, and the building became too dangerous to enter. Only the outer shell remained almost entirely intact. For more the 60 years, the complex remained largely unused.
In the run-up to the International Building Exhibition in Hamburg in 2013, the former flak bunker was transformed into an energy bunker. 25,000 tonnes of rubble were removed from the bunker, and the converted energy bunker has been in operation since April 2013.
On the initiative of the Geschichtswerkstatt Wilhelmsburg and other organisations, the IBA used a jointly developed concept to create an exhibition on the history of the former flak bunker in Wilhelmsburg. A total of 20 display cubes scattered around the entire building and placed in prominent locations explain the history of the bunker. A small book with additional information is available in the café on the viewing platform. Extensive information is also provided about the different forms of energy production (solar, pellets, combined heat and power unit, heat recovery) now used by the bunker.