L-Tower Esterhazypark (Leitturm Esterhazypark)

Haus des Meeres


Vienna, Austria

48.198, 16.353


Friedrich Tamms


Built in


The Esterházypark Leitturm is the only flak tower with a long history of civilian use. The tower has housed an underwater museum known as the Haus des Meeres since 1958. One of its outside walls also has a 700 square metre climbing wall operated by the Alpenverein (since 1998).

In 1942 Adolf Hitler decided to build six flak towers to protect the historic city centre of the so-called Gauhauptstadt Vienna from destruction from Allied airstrikes. The existing towers in Berlin and Hamburg served as models for the architect Friedrich Tamms. All the flak towers are grouped in twos, with a Gefechtsturm (combat tower) and a Leitturm (lead tower) forming one pair. These pairs of towers are arranged in a triangle around the heart of Vienna’s historic centre, the Stephansdom. Originally, the Nazis planned to convert the flak towers into gigantic victory monuments to fallen German soldiers. After the war, the towers were to have been clad in white marble. Fortunately, history turned out differently.

After the defeat of the German Reich in May 1945, the flak towers stood empty for many years. Unlike in Berlin and Hamburg, the Allies did not attempt to destroy these giant grey blocks. One reason might have been Austria’s long-standing claim as a victim of Nazi aggression. As a result, the towers remain as concrete witnesses to the crimes committed by the Nazi dictatorship and as unforgettable reminders and warnings of Austria’s culpability. But until now there has never been an active historical reappraisal. After more than 70 years, the concrete towers are now an essential and integral part of the city of Vienna and its inhabitants.

The Esterházypark Leitturm is the only flak tower with a long history of civilian use. The tower has housed an underwater museum known as the Haus des Meeres since 1958. One of its outside walls also has a 700 square metre climbing wall operated by the Alpenverein (since 1998). In 2013 a new roof superstructure with two extra storeys was added, including a shark tank, a café and a rooftop terrace. In 2009 previous adaptation plans were cancelled following a citizens’ protest. In 2015 the tower was taken over from the City of Vienna by the Haus des Meeres Club for a symbolic price of one euro. The preservation order on the building had been lifted many years previously, in 2003. After the acquisition, new modifications began in 2018 and are scheduled to be completed by 2020. In the course of the expansion, a new glass façade will change the appearance of the entire building.

For 27 years the phrase ‘smashed to pieces (in the still of the night)’ was written on the outside walls of the upper storeys. This widely visible public artwork was installed by American artist Lawrence Weiner during the 1991 Wiener Festwochen Festival and renovated in 2005. The artwork was removed in 2018 due to modifications being made to the tower, triggering a new public debate about art in the public space and the status of the flak towers themselves.

In its original state, the rectangular Esterházypark Leitturm was 31 meters wide and 15 meters long. Following the rooftop addition, it is now 47 meters high and is comprised of 11 storeys. Most of the outer walls are 2.5 meters thick and the uppermost ceiling is 3.5 meters thick.

Text by Joshua Koeb


1944Infrastructure: flak tower and air raid shelter

2018 Mixed: underwater museum “Haus des Meeres” (since 1957) and climbing structure of the “Alpenverein” (since 1998)


1944 Deutsches Reich

2018 Verein Haus des Meeres


1944 Good

2018 Good

Property Management



Form of government

1944 Dictatorship

2018 Parliamentary Republic

Spatial Planning Agency

1944 Organisation Todt and Wiener Stadtbauamt


Type of heritage and protection


2018 No longer recognised as heritage

Interview with Claudia F.


I think it’s harsh that public space is being taken away again. Just so some locked-up animals have a bigger zoo. They’re using space, public space, to create a larger enclosure for the apes. I think that’s awful. They should have left it how it was and created a green space instead. – As for the flak towers: they’re ok, and all that. Horrible to look at, but they should leave them as they are, a reminder of the war.

Interview with Thomas T.

Project Manager

I don’t know when it was built. I know that it was once a flak tower. – Essentially I think it’s good that it fulfils a purpose. I’m not a big fan of ‘art-in-architecture’, so for me, it’s ok if they do away with it. I don’t even know what they’ve currently got planned. All I know is that back then it was sold by the City of Vienna for one euro. I thought that was a bit below par. But apart from that, I’m not bothered one way or the other.

Interview with Wolfgang Bandion


Yes, during the war, wasn’t it? It was a huge building site and a big part of the park was completely altered. There are still a few trees at the entrance. It was an avenue leading up to the Esterházy Palace, back then already it was a school. And it was… it was built using huge timber formwork. So it really did make an impact. – Yes, absolutely ok! After all, we can’t historicise everything; there are plenty of towers, and I think this one has been the Haus des Meeres since 1960, and there used to be an astronomy observation station on the top before anyway. Like a little observatory. But that doesn’t exist anymore. And I think it’s a good thing. I mean, all these objections that everything has to remind us of the war, I mean, that’s just ridiculous. After all, it’s not going away, is it? Anyone with eyes in their head knows perfectly well it’s a relic from the war; it’s just been put to a different use. Better than what was originally planned, when they would all have been clad in black granite with the names of all the fallen, that’s what I had in mind.