Those are the 'Kranhäuser' (Crane Houses) in Cologne, named after their peculiar shape. I really like the geometry they form when observed from different perspectives.
A close-up of the first one. A bit grainy, since I wasn't, well, close enough. I might redo this at some point, as well as try to shoot the same thing from the other side.
A bit of a different angle.
All the pictures were taken on the Deutzer Brücke (bridge). This is what you see when you turn around.