The Prague Astronomical Clock or Prague Orloj is a medieval astronomical clock located in Prague, Czech Republic. The Orloj is mounted on the southern wall of Old Town City Hall in the Old Town Square and is a popular tourist attraction. The Orloj 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; and a calendar dial with medallions representing the months. (en.wikipedia.org/wiki/Prague_Astronomical_Clock)
