For those visiting Hamburg, Bunker St. Pauli would stand out as a fort-like structure with hanging gardens, unlike other German buildings. It recently opened its doors to people looking to stay at the hotel it houses or visit one of its restaurants.

But those familiar with Hamburg’s history know that even if the bunker only just relaunched in its modern avatar, it’s been around a long time—since 1942, to be precise. Constructed during World War II in 1942, the “Flakturm IV,” as it was called then, is a remnant of the Nazi regime. Laborers built it over just 300 days as an anti-aircraft defense structure.

Decades later, the bunker serves a very different purpose—hosting guests who want to catch a roof-top view of Hamburg or enjoy a cocktail at its bar. The robust structure, one of the largest of its kind, was among the bunkers that weren’t blown up in a “denazification process,” the property’s website says, as this could have endangered neighboring areas. It was later repurposed as a temporary housing for Hamburg residents and a TV broadcasting center before evolving into a music and nightlife venue.

The revamp, which cost €100 million , has given the bunker a different look, with a mix of concrete-like rusticity and a splash of greenery, paving the way for what the property calls “an unforgettable experience.” The project’s initial budget was €35 million. Reverb, a hotel operated by Hard Rock, is also housed in the bunker and offers 134 rooms .

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