It is surrounded by three walls. At the highest point, to the west, are the ruins of a fortress dismantled in the 16th century. Eight gates embedded in the second wall lead into the city. These gates date to the 12th and 13th centuries, the main ones being: Porta San Giovanni, behind which begins the city’s main street via San Giovanni, Porta San Matteo, and Porta San Jacopo.
There are four squares in the city center: the Pizza Duomo, Piazza della Cisterna, Piazza Pecori, and Piazza delle Erbe.
