The groove or Furlo pass is a gorge located along the original route of the Via Flaminia, in the section where it runs alongside the Candigliano river tributary of Metauro in the province of Pesaro-Urbino.
The gorge was formed between Mount Pietralatra (889 m) and Mount Paganuccio (976 m), due to the erosive force of the river Candigliano; over thousands of years has reached a considerable depth, but this is now no longer visible because of the dam, built in 1922, which reduced the rushing stream to a placid lake.
Since June 12, 2001, was established the Furlo Gorge State Natural Reserve. Hence came the Roman Emperor Honorius in 404, after the victory over the Visigoths under Alaric, to go to the triumph of Rome. Vitiges in 538, during the Gothic war fortified the pass, closed the two entrances to the tunnel and placed a garrison of 400 Ostrogoths, who were later defeated by the soldiers of Belisarius plunging above large boulders. It was subsequently occupied by Totila, powerfully fortified, but in 553 it was conquered by Narses. Between 570 and 578, the pass was taken by the Lombards who destroyed the fortifications.
In the following centuries it seems that the Via Flaminia had been almost abandoned: Lucrezia Borgia crossed it in 1502. Even in the beginning of the ‘700 the passage was difficult and dangerous, and only in 1776 the pass and the way were refitted. Between May 23 and June 12, 1849 the soldiers of the Roman Republic commanded by Colonel L. Pianciani, resisted the Austrian army.
During World War II, the Furlo lived moments of tension, but it was not the scene of fierce fighting.