Note that there is no lift and the stairs are steep and narrow. Tours can be booked at the Museo Correr, by calling 041 520 9070 or online.
The clock tower, designed by Maurizio Codussi, was built between 1496 and 1506; the wings were an addition, perhaps by Pietro Lombardo. Above the clock face is the Madonna. During Ascension week and at Epiphany, the Magi come out and bow to her every hour, in an angel-led procession. At other times of year the hours and minutes are indicated in Roman and Arabic numerals on either side of the Madonna; this feature dates from 1858 - one of the earliest examples of a digital clock in the world. On the roof, statues of two burly Moors, made of gunmetal and cast in 1497, strike the hour. Another Moore (Roger) sent a villain flying through the clock face in the film Moonraker.
After lengthy restoration, the tower reopened in 2007. The tour reveals the workings of the clock, which dates from 1753 and was a remake of the original of 1499. Until 1998 the clock was wound manually by a temperatore who lived in the tower. Amid controversy the last incumbent was replaced by an electrical mechanism. The tour concludes on the roof of the tower with a fine view over piazza San Marco, the basilica and the palace.