Astronomical Clock

The Prague Astronomical Clock (Pražský orloj), mounted on the south wall of the Old Town Hall since 1410, is the oldest working astronomical clock in the world. Built by clockmaker Mikuláš of Kadaň, it simultaneously displays four different time systems, the positions of the sun and moon in the zodiac, and the current phase of the moon — all through a single medieval mechanism. Every hour from 9:00 AM to 11:00 PM, the clock performs its famous Apostles procession: twelve wooden figures parade through two opening windows while animated allegorical figures of Death, Vanity, Greed, and a Turk move on either side of the dial. Viewing the show from the square is free; climbing the adjacent tower offers panoramic views over the Old Town.