Ouvrage Saint Ours Haut, Military museum in Val-d'Oronaye, France.

Ouvrage Saint Ours Haut is an underground military museum housed in a mountain fortress with tunnels, sleeping quarters, and command centers. The structure uses the natural landscape and contains multiple defensive positions integrated into the surrounding terrain.

The fort was built in the 1930s as part of the Maginot Line and served as a strategic defensive position on the French Alpine border. It was designed as part of a broader effort to create a continuous line of fortifications against potential threats.

The displays show how soldiers lived and communicated within this mountain fortress. The site was part of a larger network of defended positions protecting the French border across the Alpine region.

The ouvrage stands at about 1,850 m on the sunny slope of the Ubayette valley, above the hamlet of Saint-Ours; the road to the Viraysse battery passes just below it. Visits are run as part of the Saint-Ours-Bas museum, so confirm opening before setting out. Inside, a 60 cm narrow-gauge track with hand-pushed wagons runs along the main gallery, which descends at a 70% grade from the entry block.

The visible entrance block is Block 1, a mixed entry for men and munitions, since Alpine relief ruled out separate entrances. A drawbridge spanned the diamond-shaped ditch so a small van could reach the unloading hall, and the gallery beyond descends at a 70% gradient, with a cable-hauled cart for supplies.