This is one of Prague's magnets: hundreds of people gravitate here throughout the day to see the hour struck by the mechanical figures of the astronomical clock. Before the hour, look to the upper part of the clock, where a skeleton begins by tolling a death knell and turning an hourglass upside down. The Twelve Apostles promenade by, and then a cockerel flaps its wings and screeches as the hour finally strikes. To the right of the skeleton, the dreaded Turk nods his head, almost hinting at another invasion like those of the 16th and 17th centuries. This theatrical spectacle doesn't reveal the way this 15th-century marvel indicates the time -- by the season, the zodiac sign, and the positions of the sun and moon. The calendar under the clock dates from the mid-19th century.

The Old Town Hall served as the center of administration for Old Town beginning in 1338, when King John of Luxembourg first granted the city council the right to a permanent location. The impressive 200-foot Town Hall Tower, where the clock is mounted, was first built in the 14th century. For a rare view of the Old Town and its maze of crooked streets and alleyways, climb the ramp or ride the elevator to the top of the tower.

Walking around the hall to the left, you can see it's actually a series of houses jutting into the square; they were purchased over the years and successively added to the complex. On the other side, jagged stonework reveals where a large, neo-Gothic wing once adjoined the tower until it was destroyed by fleeing Nazi troops in May 1945.

Guided tours of the Old Town Hall depart from the main desk inside (most guides speak English, and English texts are on hand). Previously unseen parts of the tower were opened to the public in 2002, and you can now see the inside of the famous clock.