The small village of Castel del Piano is located in the western part of the Amiata mount, in a place inhabited since the Neolithic Age; however the name place is mantioned for the first time in a document dating 890. It was conquered by the Aldobrandeschi family and by Siena. Its name probably derives from a local castle built on a plain area.
Among the civil monuments Palazzo Nerucci, in Renaissance style, the Palazzo Comunale, with important works of art by Nasini and the remains of Roman columns, and the XIX century obelisk dedicated to Giuseppe Garibaldi, worth a visit.
Religious monuments are interesting too, such as the Chiesa Parrocchiale della Natività, built in the XVI century, rich in statues, frescoes and altars, the Chiesa del Santissimo Sacramento, built in the XIII century in Romanesque style, the Chiesa di San leonardo, the oldest one of the town, the Chiesa di San Giuseppe, also known with the name of Oratorio della Confraternita della Misericordia and the Churches of Santa Lucia, San Biagio and San Processo.