Turret clock

Modern striking turret clock movement mounted in a clock tower. Clock faces on all four sides of the tower are driven by a shaft from the movement below

Probably the most famous turret clock is located in the Elizabeth Tower at the north end of the Palace of Westminster in London and rings the bell "Big Ben"

A turret clock or tower clock is a clock designed to be mounted high in the wall of a building, usually in a clock tower, in public buildings such as churches, university buildings, and town halls. As a public amenity to enable the community to tell the time, it has a large face visible from far away, and often a striking mechanism which rings bells upon the hours.

The turret clock is one of the earliest types of clock. Beginning in 12th century Europe, towns and monasteries built clocks in high towers to strike bells to call the community to prayer. Public clocks played an important timekeeping role in daily life until the 20th century, when accurate watches became cheap enough for ordinary people to afford. Today the time-disseminating functions of turret clocks are not much needed, and they are mainly built and preserved for traditional, decorative, and artistic reasons.

To turn the large hands and run the striking train, the mechanism of turret clocks must be more powerful than that of ordinary clocks. Traditional turret clocks are large pendulum clocks run by hanging weights, but modern ones are often run by electricity.