Val di Chiana

During the Tertiary Era, the Valdichiana was part of the Tuscan archipelago; however, during the Quartenary Era the marginal area became part of the sea while the the sides rose on various levels, creating deep depressions and clay formations, conglomerations and yellow sands. A profound mutation took place when the Vulsinii volcanoes formed, including four large craters, which created a transversal barrier. When the waters came together, they formed a shell shape in the Valdarno basin to the north and the Paglia depression to the south.

Judging from the prehistoric graffiti found in caves on Monte Cetona, the Val di Chiana region south of Arezzo between the Val d'Orcia and the Val Tiberina was inhabited early on. It gets its name from the river Chiana, and the valley is a natural communication route between the provinces of Arezzo and Siena. The present-day appearance of the Val di Chiana is the result of marsh drainage and reclamation work that was started by the Romans and carried on right through the 20th century. Nowadays there are just two remnants of the original large lake, the Lago di Chiusi and the very small lake at Montepulciano.

Montepulciano is the most important town in the valley, and the ancient 16th century fortifications designed by Antonio da Sangallo il Vecchio are still standing. Its narrow medieval streets and alleys lead up to the highest point of the town, Piazza Grande, which is an excellent example of Renaissance urban design.

The historic part of Chianciano is located on a hill and thanks to the fact that the large, modern, thermal bath complexes have been built elsewhere, it has managed to preserve intact its original medieval appearance. Outside the ancient city walls there is the modern and functional town of Chianciano Terme, which plays host to more than a million visitors a year.

The town of Chiusi is situated in the hilly area in the south of the Val di Chiana and has the oldest origins of all the settlements in the valley; recent finds indicate there was settlement here in the Bronze Age.

San Casciano Bagni is the southernmost comune in the Val di Chiana, on the border with Lazio and Umbria. Its most distinctive feature is its thermal springs (the third-largest capacity in Europe).