The Umlauftank, affectionately called the “Pink Pipe” by Berliners, is a high-tech facility for testing models of ships, consisting of a 120 meter long pink circulation pipe, set on its side, topped by a blue laboratory hall. The colours reveals the function to the observer. The “pink tube” forms the water circuit. Inside, a turbine sets water masses in motion, generating a flow velocity of up to ten metres per second. Here, researchers test ships and ship models in real conditions.

Ludwig Leo (1924-2012) was perhaps the most unusual architect working in West Berlin in the post-war period.