Forte Varisello, Military fort at Mont-Cenis pass, France.

Forte Varisello is a pentagonal mountain fort at 2,118 meters (6,950 feet) altitude on the Mont-Cenis pass. The structure spans two levels with vaulted casemates and overlooks the lake and surrounding peaks.

Italian forces built the fort in 1877 to guard Val di Susa from French threats. French control came after the 1947 Paris Treaty redrew the border.

The fort's name comes from the Varisello height above the Mont-Cenis pass, and its Italian name Forte Varisello became Fort de Variselle after the plateau passed to France in 1947. Its command role is visible in the central barracks, which held the powder magazine, shell store, food stores, infirmary and bread oven. Between 12 and 17 July 1883 its electric projectors lit a military camp at night, among the first such trials in Italy.

The fort stands at 2,118 m on the height south of the Mont-Cenis lake, reached by the 700 m Strada del forte Varisello branching from the military road above Gran Croce di Venaus. The interior is closed to visitors because the structure is unstable and at risk of collapse; the 1909-1910 shelling damage on the western side is visible from outside.

The fort has underground rooms carved into the mountain for ammunition, powder storage, and supplies. These chambers kept military resources protected from attack and the harsh mountain weather.