Prague Orloj (Pražský orloj)
First installed in 1410, it is now the world's third-oldest astronomical clock, and the oldest one that is still working. The Orloj is mounted on the southern wall of Old Town City Hall in the Old Town Square.
The clock mechanism itself is composed of three main components: the astronomical dial, representing the position of the Sun and Moon in the sky and displaying various astronomical details; "The Walk of the Apostles", a clockwork hourly show of figures of the Apostles and other moving sculptures—notably a figure of Death (represented by a skeleton) striking the time; and a calendar dial with medallions representing the months.
(Wikipedia, 2012)
