Haus des Meeres – Vienna's Unique Aquarium & Flak Tower Experience

In November 1957, volunteers began occupying the flak tower. Initially, the ground floor and bunkers were used by firefighters, leaving only a small habitable space for the aquarium exhibition. The rest of the tower was filled with debris.

The Haus des Meeres, an aquarium located in Vienna, Austria, opened in 1957. It houses over ten thousand aquatic beings within a former World War II flak tower.

The concrete tower that now houses the Haus des Meeres was built as a fire control flak tower. Its construction took ten months, from October 1943 to July 1944.

The flak tower is 47 meters tall with a footprint of 31 by 15 meters. In 1944, it was topped with a Würzburg radar dome, which could be lowered into a protected shaft in case of air raids.

The building housing the Haus des Meeres is a flak tower that was constructed during World War II. It was part of a combat unit with two other pairs of flak towers in Vienna.

After World War II, the flak tower in Esterhazy Park was temporarily used as a hotel with 38 rooms within the bunker. It was later converted into a fire station before becoming the site of the aquarium.

An extensive renovation took place in 1997, replacing the original 1944 elevator. This renovation enabled the opening of three new floors, expanding the exhibition space.

Glass wings were added to the Haus des Meeres in 2000 and 2007. These extensions house the reptiles and tropical birds sections of the aquarium.

In 1991, the building was adorned with a slogan against war and fascism by American artist Lawrence Weiner. This artwork eventually became a focus of debate regarding its artistic heritage and maintenance costs.

In 2007, the Haus des Meeres installed its largest tank, holding 300,000 liters for sharks. The initial six blacktip reef sharks moved into the tank died shortly after, attributed to stress.

In 2007, the Austrian Post issued a commemorative stamp celebrating the 50th anniversary of the Haus des Meeres. The stamp featured the gravel from recycled World War Two concrete used in the new shark tank.

Despite the 2008 financial crisis impacting other Viennese museums, the Haus des Meeres saw a steady increase in visitor numbers. By 2009, it ranked among Vienna's top ten tourist attractions by ticket sales, even with a ticket price increase.

The Haus des Meeres is managed by Aqua Terra Zoo, a private non-profit organization. It receives minimal financial support from municipal authorities, while the taxpayer covers the maintenance costs for the former flak tower.

Due to expansion plans and the installation of an artwork, the City of Vienna removed the tower from its list of protected landmarks. However, preservation of the artwork was enforced.