First installed in 1410, the Prague Astronomical Clock is the oldest working astronomical clock in the world. The clock is mounted on the southern wall of the Old Town Hall in the Old Town square in central Prague.
Every hour a parade of 12 apostles appears while other figures join in the fun, notably a figure of death who strikes the hour. An astronomical dial represents the position of the sun and moon in the sky and other astronomical details. A calendar dial represents the months.