The Pianetto Castle was built to defend the Abbazia di Sant ‘Ellero in the XI-XII century. Of the entire structure only some imposing ruins have been preserved: part of the walls, a semicircular tower that preserves the water collection tank, the south and north gates and the tower of the keep. Under the tower there is an entrance that was probably the ancient access to the underground.
The Rocca’s interesting position has meant that the castle represented a strategic point of considerable importance. Many were among abbots, condottieri and the same Holy See to contend the majestic building.