The roughly circular walls, totalling a length of about 570 metres (1,870 ft) 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 piazza, 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 without.

Other sights in the town's countryside include:
Badia of Santi Salvatore e Cirino, at Abbadia Isola, a Romanesque abbey from the mid-12th century.

Romanesque church of San Lorenzo a 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
The roughly circular walls, totalling a length of about 570 metres (1,870 ft) 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 piazza, 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 without.
Other sights in the town's countryside include:
Badia of Santi Salvatore e Cirino, at Abbadia Isola, a Romanesque abbey from the mid-12th century.
Romanesque church of San Lorenzo a 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
Monteriggioni