The Prague astronomical clock was installed in 1410 on the southern wall of the Old Town Hall in Prague's Old Town Square. It was the third such clock in the world and the oldest one still operating. The oldest part of the clock was made by Mikulas of Kadan, a clockmaker, and Jan Sindel, who would later teach mathematics and astronomy at Charles University. Some eighty years later a calendar dial was added, as well as gothic decorations. Over the years, other features -- statues, figures of the apostles, a crowing rooster -- were added. The clocks astronomical dial shows the position of the sun and the moon. "The Walk of the Apostles" features moving statues, including Death striking the hour. The calendar dial shows the months.
The video below shows the 600th anniversary celebration of the clock on this date in 2010.