Furlo Gorge Nature Reserve covers an area of 3.626,94 hectares of protected land. It was established in 2004; the towns included in the reserve are: Acqualagna, Cagli, Fermignano, Fossombrone, Urbino. For many centuries it was a strategically important trade route along the Via Flaminia linking Rome to Rimini. At one point the ancient highway passes through a tunnel hewn by hand through the hard rock. The work was ordered by Emperor Vespasian in 76 AD – a remarkable feat of Roman civil engineering. Chisel marks in the rock can still be seen. Sponges, Foraminifera, and Brachiopods, especially ammonites are widespread all over the area. The vegetation is varied: there are holm oaks , oaks and pastures . The sheer limestone crags of the Furlo Gorge are home for the golden eagle, the lanner, the sparrow hawk and the harrier. Well worth a visit is the small romanesque Abbey of San Vincenzo, on the Acqualagna side of the gorge.