During the Middle Ages, Rostock was surrounded by stone walls. They averaged ten feet high and 3.5 feet thick. Outside the wall was a moat. Inside were platforms behind the battlements for soldiers to stand on during battle. Interspersed along the ramparts were six, octagon-shaped towers. The Busch tower is all that remains of the original defenses. It was reconstructed on the foundation of a previous tower in 1825. In the background is the spire of the Steintor gate.