BASA Bunker, Military communications bunker in Kreuzberg, Berlin, Germany

BASA Bunker is a World War II telecommunications bunker on the Hallesches Ufer in Kreuzberg, beside the Landwehr Canal and within sight of the German Museum of Technology. Its visible upper storey has exterior walls about two metres thick, and two lower levels lie beneath it, giving the complex a floor area of 4,000 square metres. Built from 1942, it housed the railway's telephone equipment, and in 1944 the Reichsbahn's first four-wire exchange was put into operation here.

The structure was built in 1942 to protect the German National Railway's telephone network during World War II. It served as a central control station for coordinating troop movements and was a key military communications hub in the city.

The structure now hosts the Feuerle Collection, displaying contemporary international art alongside Chinese imperial furniture in its transformed underground rooms. Visitors experience a striking contrast between the raw concrete walls and the refined art presentation.

The bunker is located at Hallesches Ufer near Anhalter Steg footbridge and sits within easy viewing distance of the German Museum of Technology. Visitors should expect stairs when exploring the underground exhibition areas, as access to the lower levels involves multiple steps.

The bunker used advanced telephone switching technology from Siemens & Halske that allowed direct connections between stations without needing central operators. This technology was cutting-edge at the time and made the facility a technical achievement of its era.