Piazza del Comune (the Main Square of the town) is situated at the heart of the town and built on the site of the ancient Roman forum. The square is surrounded by ancient medieval buildings, and a fountain stands in the middle.

To the side of the Palazzo del Capitano del Popolo, a turreted the 13th century building, stands the beautiful Municipal Tower from the 14th century in which the "Bell of Lauds" was placed in 1926.

The left side of the Piazza del Comune is closed by the Priors' Palace from 14th century, which nowadays houses the town council offices, and the Municipal Picture Gallery, containing frescoes by the Byzantine, Umbrian and Siennese school, as well as those painted by the followers of Giotto, paintings by Nelli, Alunno and Tiberio d'Assisi.