Impregnable and mighty, they dominate boundless valleys: these are the fortresses that still rise with all their splendor in the territory of Amiata. Arcidosso, Piancastagnaio, and even Selvena in the municipality of Castell’Azzara still preserve extraordinary examples of medieval fortresses. Unique, for instance, is the Aldobrandeschi Castle of Arcidosso, which is the oldest extramural state government building in Italy and one of the oldest in Europe. Today, the rooms of these fortresses house museums and classrooms, or, as in the case of Rocca Silvana, are places to visit to learn about the past history of this mountain.