The Furlo Gorge is a deep and narrow split that separates Mount Paganuccio (976 m) from Mount Pietralata (888 m); it is characterized by almost vertical walls engraved in the limestone. There flows the Candigliano River, a tributary of the Metauro river; the river, at the narrowest point of gorge, tops with a waterfall a sharp drop of about 10 m, where it was later built a dam that runs along the famous Via Flaminia. One of the itineraries of the area is the Waterfall of the Swallows, an extremely vertical and scenic route. Canyoning is possible in case of heavy and frequent rainfall.