Whilst in the Old Town Square, time your visit to the Old Town Hall so that you can watch the spectacle of the mechanical clock marking the turn of an hour. The clock itself is on the south face of the town hall and is the pride of Prague. 

It was built in the fifteenth century and despite being damaged and repaired during its lifetime, it is widely regarded as the best preserved medieval mechanical clock in the world. The show at the top of the hour never fails to disappoint the many onlookers.