Fort de l'Olive, Military fortification in Briançon, France.

Fort de l'Olive is a military fortification built high in the French Alps with substantial stone walls occupying a large footprint on the mountainside. The installation dominates the surrounding landscape and its position commands several key passes through the mountains.

Built in 1881–1882, the Fort de l’Olive was the third and last fort planned by General Séré de Rivières in 1874 to shield Briançon. First named Ouvrage du Bois des Gasquets, it was armed with fourteen 120 mm guns and housed 143 men. In the 1930s two casemates for 75 mm guns were cut into the north slope; in June 1940 it exchanged fire with the Italian Fort Jaffereau.

The fort's original name was Ouvrage du Bois des Gasquets before it took the name of the l'Olive site. Its 1930s infantry shelter was nicknamed Fort des Nuages, the fort of the clouds, because of its altitude of 2,239 m. Local memory still tells of Lieutenant Meyer, who vanished here in 1887 and was found dead a year later.

Visitors reach the fort via a mountain hiking trail that requires several hours of walking and good physical fitness. The terrain is steep and exposed, so weatherproof gear and proper footwear are necessary.

In June 1940 the fort exchanged fire with the Italian Fort Jaffereau at Bardonecchia while itself under shelling from Fort Chaberton, built 900 m higher on the Italian side. The 1930s infantry shelter added uphill was nicknamed the Fort des Nuages, the fort of the clouds.