Cardinal Albornoz, a power-hungry zealot tasked with rebuilding and strengthening the papal states, arrived in Spoleto in the mid-14th century and commissioned the Umbrian architect Matteo Gattapone to build a fortress. The site was perfect—atop a high hill above the town and, as history would prove, virtually impregnable. The walled-and-moated castle became famous in the 20th century as one of Italy’s most secure prisons, where members of the Red Brigades terrorist organization were routinely incarcerated. The fortunate ones might have had a view through their cell windows of the majestic Ponte delle Torri, a 232m (760 ft.) long aqueduct built in the 13th century on Roman foundations. Its arches span a deep, verdant gorge, 90m (295 ft.) above the Tessino river, a scene that so impressed Wolfgang von Goethe on a 1786 visit to Spoleto that he dedicated an entire page of his “Italian Travels” to the spectacle.

The current occupant of the fortress is the Museo Nazionale del Ducato di Spoleto (tel 0743-223-055), with a benumbing collection of sarcophagi, mosaics, and religious statuary that you needn’t feel guilty about not seeing (and it’s very expensive as well). The views of the town and Umbrian countryside from the grounds are free and well worth the ride up, via a series of escalators and elevators.