A small Romanesque parish church on the lower edge of the old town, San Pietro alla Carità is worth ten minutes for one striking detail: the central nave is supported by twelve mismatched ancient columns, plundered from the nearby Roman ruins when the church was first built in the early Middle Ages.
The columns are of different stones and proportions — granite, marble, cipollino — and even the capitals do not match. The effect is one of those wholly unselfconscious medieval improvisations on the Roman past that you find only in central Italy.