the war; one side remains visible. The interior can be visited. . The L-Tower was partially demolished after the war; some walls remain visible. Flakturm IV – Heiligengeistfeld, Hamburg Heiligengeistfeld (1st Generation) This tower contains six levels below the rooftop and includes in its design, as part of its air-raid shelter, two identical spaces for protection against gas attacks. One is located 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). The L-Tower was demolished after the war and replaced by a building owned by T-Mobile. . The G-Tower was transformed into a nightclub with a music school and music shops. In 2019 the NH Hotel Group announced plans to turn it into a luxury hotel with a forest on top of it, with construction to take place in 2021 and opening in 2022. After the reconstruction the height was to increase to 58m with some additional floors. There were to be thirteen stairs. 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 Stiftskaserne (3rd Generation) G-Tower's interior is used by the Austrian Army. L-Tower (in Esterhazypark) has been used as a public aquarium, the Haus des Meeres, since 1957. The outside of the L-Tower was re-purposed as an outdoor climbing wall. Flakturm VII – Augarten, Vienna Augarten (3rd Generation) G-Tower remains empty. The entire north-east and half of the east 20 mm gun platforms, including the connecting walkways, were removed in 2007 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 – Arenbergpark, Vienna Arenbergpark (2nd Generation) G-Tower is used as a storehouse for art. L-Tower