The former Flak tower was 47,3 m high, 31 m long and 15 m wide, excluded the new roof construction open in September 2013.
The picture nr. 1 shows the Esterhazy Park in 1938 and the picture nr. 2 the Flak tower in 1954. The tower was erected between October 1943 and July 1944, after only 10 months of construction and used as anti-aircraft gun blockhouse until the end of the war. Among other things there was so called “Würzburgreise” on the roof which was a radar protected by 3,5 m thick concrete walls.
If you want to know whom & what in which floor to expect, have a look at the Floormap.
You can find more details about the history of the Haus des Meeres in the History.
The Flak tower was managed by the union, since 1992 by the city of Vienna. The sale of the tower to Haus des Meeres was unanimously approved by the municipal authority of Vienna on 1.7.2015.
The record into the land registry followed on 31.8.2015.
However even after the sell of the Flak tower the city of Vienna remains the responsible owner of the work of art from Lawrence Weiner.