The importance of this place was due to its strategic position on the hills it stands on, on the border between Arezzo and Siena. For this reason, a fortress, walls and a tower were added onto Castello di Marciano between the end of the 13th century and the beginning of the 14th century. The singular trapezoidal structure shows the military nature of this architecture, which differs from the castles of neighbouring villages that were used as homes.
Today the castle, which has been restored, is home to a multifunctional Cultural Centre. There is a beautiful view over the Valdichiana from the tower.
To visit the historic centre, you have to go through the door above the tower. Inside the town, there are several imposing fortresses, in the typical Sienese style. The Church of Santi Stefano and Andrea is also worth seeing, whose original structure was restructed in 1700s, and which is home to a canvas by Bartolomeo della Gatta depicting Madonna and child with Saints.