The castle of Poggiarello is located along the road that connects Caldana to San Giusto a Balli. The place is mentioned at the end of the thirteenth century in the Road Statute of Siena, but we know nothing about the history of the castle. The hamlet has a tower with a sloping base, and a second building also with battlements. Southward there are two sections of ancient walls with a guard tower at the corner, bordering a small courtyard. In the garden there is a chapel dedicated to S. Augusto and built in 1558 by Augusto Chigi, perhaps on a design of Baldassare Peruzzi.