The roughly circular walls, totalling a length of about and following the natural contours of the hill, were built between 1213 and 1219. There are 14 towers on square bases set at equidistance, and two portals or gates. One gate, the Porta Fiorentina, opens toward Florence to the north, and the other, the Porta Romana, faces Rome to the south. The main street within the walls connects the two gates in a roughly straight line. The main town square, the Piazza Roma, is dominated by a
Romanesque church with a simple, plain façade. Other houses, some in the
Renaissance style (once owned by local nobles, gentry, and wealthy merchants), face into the piazza. Off the main piazza smaller streets give way to public gardens fronted by the other houses and small businesses of the town. In more hostile times, these gardens provided vital
sustenance when enemies gathered around the walls during
sieges. Other sights in the town's countryside include: •
Badia of Santi Salvatore e Cirino in
Abbadia a Isola, a Romanesque abbey from the mid-12th century • Romanesque church of San Lorenzo in Colle Ciupi • Romanesque
Pieve of Santa Maria a Castello, known since as early as 971 • Romanesque-
Gothic hermitage of
San Leonardo al Lago •
Villa Santa Colomba ==Cultural significance==