Haus des Meeres

The Haus des Meeres in Vienna's Mariahilf district is an aquarium and terrarium complex inside the former Esterhazypark flak tower, a monumental Wehrmacht anti-aircraft bunker of 1944. Opened in 1957, the place has climbed eleven storeys up the indestructible concrete block with glass extensions and a 360-degree sky bar. Around 10,000 animals live here today: sharks and rays in a 300,000-litre Atlantic tunnel, crocodiles, snakes, free-roaming small monkeys and tropical birds in the Crocopark hall, creepy-crawlies in the Terrazoo. One floor exposes the raw flak-tower concrete with a historical exhibition. The roof opens clear views over Vienna; weekends pack families in front of the shark tanks.