It was constructed as a display of Venice's wealth, and as an aid to sailors on the Grand Canal about to depart on a voyage.
The building was constructed between 1496 and 1499. It is topped by a single story tower with the Lion of St Mark against the night sky, while two blackened bronze figures intended as giants but known as the "Moors" stand on top and ring a bell on the hour.
The clock mechanism, dating from 1499 and much restored since then, drives the clock. On the left side the hours are shown by the numbers 1 to 24 in Roman numerals. A sun is fixed at the end of the hour hand. The second dial depicts the twelve signs of the zodiac, These dials are decorated in gilt on an enamel blue background. The inner dials indicate the phases of the moon and sun.
There is a nich with a statue of the Virgin Mary and baby Jesus. On Ascension Day, statues of the Three Kings pass in front of the displays.
Major renovations have obscured the structure behind scaffolding for several years. Now though, this extraordinarily elaborate timepiece is on public show again, in full working order, and delighting visitors and Venetians alike, as it has done for more than 500 years.