Flakturm IV

The Green Bunker (Grüner Bunker) in Hamburg's St. Pauli district is a historic World War II flak tower that is now considered a modern landmark of the city. The massive concrete structure was originally built in 1942 to protect the population from air raids. With a footprint of 75 by 75 meters and a height of 38 meters, it is one of the largest high-rise bunkers ever built. The walls are 3.5 meters thick, giving the building enormous strength. After the war, the bunker initially served as housing and emergency shelter before being converted into a media center in the 1990s. During this period, it housed music clubs, agencies, and a large musical instrument store, among other tenants.

The site's present-day character is the result of a comprehensive renovation between 2019 and 2024. The listed building was topped with five additional stories and covered in extensive greenery that includes both the façade and the roof. A special feature is the 550-meter-long Bergpfad (Mountain Trail), a staircase mounted on the outside of the building that leads to a rooftop garden open to the public. The garden covers 1,400 square meters and is home to thousands of perennials and woody plants chosen specifically to withstand the extreme wind conditions on the roof. The project is regarded as a showcase for urban climate adaptation and has received international awards.

Today, you can experience the bunker in a variety of ways. The rooftop garden offers sweeping panoramic views over Hamburg and is a popular spot for relaxation and cultural events. Inside the expanded building you'll find the Hotel Reverb, which has several restaurants and bars. The Georg Elser Hall is also available and is used for sporting events and concerts. The former media bunker continues to house cultural institutions, so the site combines historical significance, modern architecture, and urban nature.