The squat brick tower of Sant'Andrea sits at the southern end of the Corso del Popolo, attached to the small church of the same name. The lower courses of stone date to the 11th or 12th century, when the tower formed part of the town's defences against pirates and rival lagoon powers.
The real attraction is upstairs: the original 14th-century clock mechanism, still ticking after more than six hundred years, has been beautifully restored and put on display in a small museum at the top of the tower. The climb is steep but rewarded by panoramic views over Chioggia, the lagoon, and the long line of Sottomarina beach.