THE PRAGUE ASTRONOMICAL CLOCK

 

Old Town Hall, Prague

From Wiki: 

The Prague astronomical clock or Prague Orloj is a medieval astronomical clock mounted to the south wall Old Town Hall in the Old Town Square in Prague, the capital of the Czech Republic.

Getty Images

Steve Collis

The clock was first installed in 1410, making it the third-oldest astronomical clock in the world and the oldest clock still in operation. It was created by clock maker Mikuláš of Kadaň and Prague's Charles University professor of mathematics and astronomy Jan Šindel.

The clock mechanism has three main components – the astronomical dial, representing the position of the Sun and Moon in the sky and displaying various astronomical details; 

statues of various Catholic saints stand on either side of the clock; "The Walk of the Apostles", an hourly  show of moving Apostle figures and other sculptures, notably a figure of a skeleton that represents Death striking the time; and a calendar dial with medallions representing the months.

For more details on how the clock works: https://www.bigboytravel.com/czechrepublic/prague/how-to-read-the-astronomical-clock/