Just south of Trevi, along the Via Flaminia near Campello sul Clitunno, stands one of the most unusual early Christian buildings in Italy. The Tempietto del Clitunno looks, at first glance, like a small Roman temple: a classical pediment, four columns, a carved frieze. It is in fact a small church dating from the late 5th or early 6th century AD, built using ancient Roman stonework and decorative elements cannibalized from earlier structures on the same site.
The interior is tiny — barely large enough for a dozen people — with a frescoed apse showing Christ flanked by Saint John and Saint Peter, painted in a severe early Christian style. Beside the building, the Fonti del Clitunno spring rises from the hillside into a small natural pool, surrounded by weeping willows and white poplars. The Roman poet Virgil and the Emperor Caligula both recorded a visit. Lord Byron wrote a verse about it. It remains one of the more inexplicably serene spots in Umbria.