An ancient mill, built by the city of Siena in 1246, at the time of Podestà Gualtieri da Calcinaia, as you can read above the entrance. In 1258 the property was divided into parts and sold to different buyers. Up until mid 1900s the mill continued to be used for grinding cereals. It used the water from a canal parallel to the road and from the river Rosia. A tiny chapel, recently restored, is dedicated to S. Caterina of Alexandria.