Gambassi Terme stretches as far as the borders of the province of Siena.
It has an attractive public garden outside the Palazzo Civico which houses a small collection of Etruscan and Roman finds excavated in the area. The town was already known in medieval times for its glass production (still manufactured here).
In addition to the healing properties of the "Acqua Salsa" thermal spring, Gambassi terme has many important artistic monuments, such as the Parish church of Santa Maria Assunta, also mentioned by the Arcibishop of Canterbury, Sigerico, during his trip in Italy; the Church of Santa Cristina (1935), the Church of cristo Re (1941) and the Abbey of San Pietro in Cerreto.