St Mark's Clocktower

The Clocktower on Piazza San Marco rose between 1496 and 1499, commissioned by the Republic from architect Mauro Codussi to house an unusually elaborate astronomical clock. The mechanism itself was the work of a father-and-son pair of clockmakers from Reggio Emilia, Gian Paolo and Gian Carlo Ranieri: Gian Paolo, already an established clockmaker in his home city, won the commission in 1493, but died before the work was complete, and his son Gian Carlo finished it in time for the tower's inauguration.

Not long after, two lateral wings were added to Codussi's original design so the tower would align with the arcades of the Procuratie Vecchie flanking the square. The clock's gearing has needed periodic overhauls ever since to keep such an intricate 15th-century mechanism running — it still tracks not just the hour but the position of the sun in the zodiac and the phase of the moon, a level of astronomical detail rare for a public clock of its age.

Atop the tower, two over-life-size bronze figures swing their hammers against a great bell to strike the hour. Venetians call them "the Moors," but the nickname has nothing to do with ethnicity: it comes simply from the dark patina their bronze surfaces took on over the centuries. A persistent local legend claims the Republic had the clock's makers blinded once their work was finished, so they could never build its equal elsewhere — a colourful story with no historical basis, since Gian Carlo Ranieri is recorded going on to maintain the clock himself for years afterward.

Beneath the great blue-and-gold dial with its gilded zodiac symbols sits a golden winged lion of St Mark, and during Ascension week and at Epiphany the tower puts on a small mechanical spectacle: a door opens and a procession of the Three Magi, led by an angel sounding a trumpet, emerges to pass in front of a statue of the Madonna and Child before retreating inside — a tradition of automated devotion that has drawn crowds to the square for over five centuries.

The Clocktower can only be visited on a small, timed guided tour that climbs the tower's steep internal staircases past the astronomical mechanism itself and out onto the roof terrace, right beside the two bronze Moors and their bell — a vantage point over Piazza San Marco you won't get any other way.

Group sizes are deliberately kept small and tours run in multiple languages at set times through the day, so slots fill up fast in high season; booking online well ahead of your visit is strongly advisable rather than turning up hoping for space.