The old town of Spoleto is full of Roman remains. The amphitheatre near Piazza della Libertà, the Roman theatre (now used for festival performances), and a well-preserved 1st-century house on Via di Visiale all survive. Some of the steep, twisted streets with buildings forming arched bridges across them are worth exploring for their own sake — the layers of Roman, medieval, and later construction blend together in ways you rarely see so clearly.
Spoleto was a significant Roman colony — Colonia Julia Felix Spoletina — and its strategic position on the Via Flaminia made it wealthy. You can see that wealth in the stonework: massive blocks, fine detail, buildings that have been inhabited and modified for 2,000 years without ever quite losing their Roman bones.