The clock located on the Torre di Sant'Andrea (St. Andrew Tower) in Chioggia is one of the world's oldest working clocks. The first document citing its existence dates back to 1386. The clock may actually be even older, as a 14th-century war destroyed most of the documents written before and during the conflict.

The construction of the clock is attributed to the Dondi family. Said family was also called "Dondi dell'Orologio" ("Dondi of the Clock") after Jacopo de'Dondi designed the Astronomical Clock of Padua in 1344. The clock features just one hand, and its quadrant is divided into 24 sections. It was repaired in 1424, and during the 18th century, the original mechanism was replaced with a pendulum. These days, it works with the help of electricity while keeping its original appearance. There is a debate as to whether the clock is the actually the world's oldest, but the clock at England's Salisbury Cathedral also has a competing claim, seeing as it also, coincidentally, dates to 1386. 

Originally placed on Palazzo Pretorio, the clock moved to its current position after a fire in 1817 destroyed its original building. It was then decided to leave the clock on its new location on the Torre di Sant'Andrea, which also became known as Torre dell'Orologio (Clock Tower).

The Torre di Sant'Andrea also serves as bell tower for the nearby Church of St. Andrew, but it was built centuries before the church. Probably erected around the year 950, some studies date the structure between the 7th and 8th centuries. It has also been suggested that it could have originated as a Roman-age lighthouse. The tower now hosts a museum on the history of Chioggia.