Clock Tower

The clocktower was one of the many buildings introduced in the Prisoner of Azkaban film. There is an old courtyard at its base, and at the top is the glass face of a massive clock. There are many gears and bells inside that run the tower. Flights of wooden stairs lead up to the fifth floor at which the Clocktower ends. In the books it is said that there are bells to signal the beginning and end of classes. This is presumably why the Clocktower was placed into the films.