This small town in Upper Tuscia, between Tuscany and Lake Bolsena, is located in a broad basin that was once known as Val di Lago. The surrounding countryside has an abundance of mineral water rich in magnesium, sulphur and iron salts, and characteristic soffioni, caused by gases ris­ing from the subsoil, can be observed here. The historic centre is distinguished by the Palazzo Ducale built by the Farnese family in the seventeenth century, the sixteenth-century fountain of Duke Pietro Farnese (1648) and the church of San Clemente, rebuilt in the seventeenth century over previous Romanesque structures. The slender Borromini-style bell tower dates to 1790.

Inside the church there are paintings from various different eras, a lovely wooden crucifix, the baptistery (1591) and an organ made by Angelo Morettini in around 1865. The Earth Museum - Museo della Terra - is a delightful discovery located in an ancient Cistercian convent in the oldest part of town.

This exhibit, put together with admirable scientific precision, contains various artefacts representing the farming culture that were once part of the "Luigi Poscia" collection.