Crowds congregate in front of Old Town Hall's Astronomical Clock (Orloj) to watch the glockenspiel spectacle that occurs hourly from 8am to 8pm. Built in 1410, the clock has long been an important symbol of Prague. According to legend, after the timepiece was remodeled at the end of the 15th century, clock artist Master Hanus was blinded by the Municipal Council so that he couldn't repeat his fine work elsewhere. In retribution, Hanus threw himself into the clock mechanism and promptly died. The clock remained out of kilter for almost a century.
It's not possible to determine the time of day from this timepiece; you have to look at the clock on the very top of Old Town Hall's tower for that. This astronomical clock, with all its hands and markings, is meant to mark the phases of the moon, the equinoxes, the seasons, the days, and numerous Christian holidays.
When the clock strikes the hour, a kind of politically incorrect medieval morality play begins. Two doors slide open and the statues of the Twelve Apostles glide by, while the 15th-century conception of the "evils" of life -- a Death skeleton, a preening Vanity, a corrupt Turk, and an acquisitive Jew -- shake and dance below. At the end of World War II, the horns and beard were removed from the moneybag-holding Jew, who's now politely referred to as Greed.
A View with a Warning -- It's worth climbing the Old Town Hall's tower for an excellent view over the red rooftops of Staromestské námestí and the surrounding area. But be warned: The steps are narrow, steep, and quite physically demanding, so the less courageous should take the elevator.