Furlo Pass

The Furlo Pass is a gorge on the ancient Roman road Via Flaminia in the Marche region of central Italy, where it passes near the Candigliano river, a tributary of the Metauro.

The gorge was formed between the Pietralata and Paganuccio mountains by the river Candigliano, which whooshed in full spate through the district until it was dammed in 1922. Since 2001 it has been included in a State Natural Reserve of the same name. It is often marketed to tourists in the region as the "Grand Canyon of Italy."

The Roman emperor Vespasian had a tunnel built here to facilitate passage on the Via Flaminia at the narrowest point of the gorge. Next to it is a similar but smaller tunnel dating from Etruscan times.

Source: Wikipedia