Buco di Viso is the oldest alpine tunnel in Italy, and was opened in AD 1480 for trading purposes. Although at high elevation, the tunnel prolonged the trading season (due to snow) by a couple of months as it avoided going through the Colle delle Traversette.
More details about this tunnel can be found here.
Half-Day Run: The tunnel is located about three hours of running on steep terrain from the parking lot located at Pian del Re. It is also accessible from the French side.
Gem Type: Historic Site