The Prague Orloj - The Prague Astronomical Clock Stock Photo

The Prague astronomical clock, or Prague orloj is a medieval astronomical clock mounted on the southern wall of Old Town Hall in the Old Town Square. The clock was first installed in 1410, making it the third-oldest astronomical clock in the world and the oldest one still operating. In the background is the Church of Our Lady before Týn - The Romanesque church from the 11th century was in the 13th century replaced by a Gothic structure.