The NH Hotel Group is turning a former World War II Nazi bunker in Hamburg, Germany into a luxury hotel, Travel Pulse reported.

According to Forbes, the Spanish hotel chain will begin construction on a 136-room hotel at the St. Pauli bunker, with highlights including a bar, coffee shop and a restaurant. The property is currently scheduled to open in mid-2021.

The five-storey hotel will also include a roof-top garden and public park for hosting memorials for the victims of the Nazi regime. There will be spaces for culture, exhibitions and a hall for sports and entertainment events as well.

The historic bunker was constructed in just 300 days by more than 1,000 forced laborers from concentration camps. It was used during World War II to shelter up to 30,000 people and launch anti-aircraft fire at allied planes.

“I am very proud that (the hotel) can be built in this extraordinary location as part of this fascinating project. Of course, we are aware of the history of the bunker and its significance for the city of Hamburg,” Maarten Markus, Managing Director Northern Europe of the NH Hotel Group told Forbes.

“For us, it was crucial that the hotel should be open-minded in the creative district and, in addition, show responsibility towards the history of the bunker. This is an outstanding realization of the individuality of the ‘nhow design’: it respects the history and at the same time points into a hopeful future,” added Paul Hahnert, Managing Director EHP and Project Manager.

Currently, the nightclub Uebel&Gefährlich on the top floor is a popular destination for lovers of electronic music, while the ground floor is home to a large music store. A prestigious pop music school as well as several artists, actors and musicians, Hamburg.com reported.

In response to Berlin air-raids by Allied Forces in 1940, the Nazi regime issued an immediate decree to build air-raid shelters in cities all across the Third Reich.

Hamburg, a central location for the U-Boot (submarine) and oil industries, was deemed an obvious target. At the end of WWII, Hamburg counted no less than 1,051 bunkers — more than any other German city.

Today, there are still some 650 bunkers left. Most are more discreet than the Hochbunker in St. Pauli and are located underground or hidden behind residential buildings.