Alexanderplatz is a square in the centre of Berlin which is a hive of activity. Formerly a cattle market and military parade ground, it had been heavily bombed in World War 2 and later became part of East Berlin. After reunification Alexanderplatz was redeveloped with new buildings. It is also a hub of the transport network, with underground trains and trams bringing half a million commuters through the plaza every day. Several important buildings from the pre-war and East Berlin era still stand, including the Centrum department store (now Kaufhof), World Clock and the teachers’ building.