The Feldstrasse Bunker, also called the Medienbunker, is one of the most extraordinary surviving buildings of the Third Reich. The 38-metre concrete cube was built in 1942 as an anti-aircraft tower and shelter for up to 25,000 civilians, completed in eight months by forced labour. Its walls were intended to survive direct bomb hits and have proved so resilient that demolishing it has never been seriously attempted.
In 2019 a five-storey green-tiered hotel and public garden was added on the roof, doubling the height. A 560-metre spiral planted walkway climbs the western façade, free and open to the public, and the top now hosts a viewing platform and a restaurant with one of the best harbour views in Hamburg. The lower floors hold a long-running music school and several clubs.