This light-filled loft in Hamburg’s Ottensen neighbourhood started life as an impenetrable WWII air raid shelter.

Built in 1939 to provide protection for patients and staff at the maternity hospital opposite, Ottensen Bunker has four-metre thick concrete walls.

‘When we found the bunker it was a complete mess,’ says the apartment’s owners, design duo Ruth Kramer and Thomas Schacht. ‘It needed a lot of phantasy and ideas to imagine what it could be like.’

The former bunker has been stripped back to its bones, and carved into loft-like spaces with floor-to-ceiling windows.

This one-bedroom apartment takes up the entirety of the converted bunker’s fourth floor and the modern holiday home is available to rent via Welcome Beyond from March 2017.

Kramer masterminded the apartment’s industrial-inspired interiors, which feature smooth concrete floors and rough textured walls, offset by bronze, wood and marble details in the bathroom and kitchen. A crittall-style glass wall separates the bedroom from the open-plan living areas, and rooms are furnished with design pieces from Arne Jacobsen, Eero Saarinen, Cassina and a Bulthaup kitchen.

A short walk from the Elbe river, the bunker is also close to cafés, shops and parks. You can glimpse the freshly completed Elbphilharmonie building from its balcony, which overlooks the city’s rooftops.

Read next: How German’s wartime bunkers are being reborn