San Gimignano is a small walled medieval hill town in the province of Siena, Tuscany, central Italy. It is mainly famous for its medieval architecture, especially its towers, which may be seen from several kilometers outside the town. Important families built fortified tower houses that fulfilled practical and prestigious ends and provided effective defence against attack from without and within the town walls .The towers of such families as the Ardinghelli (Ghibelline) and the Salvucci (Guelph) reflected their continual rivalry. In the 14th century San Gimignano boasted 72 towers, of which 15 have survived. Statutes ruled that private towers should not exceed the height of the chief civic towers. The Torre Rognosa ('Scabby Tower') of the Palazzo del Podesta (1255), the oldest surviving civic building, is 51 m high. The Torre Grossa (1311) is 54 m high). The town center is a UNESCO World Heritage Site.