Introduction to the Olomouc Astronomical Clock: The Olomouc Astronomical Clock (Olomouck orloj) is located on the north wall of the Olomouc City Hall. It was built in the 15th century AD and was damaged in World War II, 1947 Rebuilt in 1955, it was one of the few astronomical clocks in the world that embodied the heliocentric theory. The astronomical clock is equipped with various puppets, and the time-telling performance at 12 noon every day is very interesting.