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

Ouvrage Saint Ours Bas is a monobloc fortification in the Ubayette valley, at 1,450 meters altitude upstream of Meyronnes in Val-d'Oronaye. Its single combat block serves as both entrance and casemate, with two levels and no underground galleries. The flat concrete roof carries two machine-gun cloches and a low parapet, and a curved retaining wall encloses a paved forecourt.

The fort was built between 1931 and 1938 as part of the Maginot Line to defend the French-Italian border. It was equipped with machine guns and a 50mm mortar and served as a key defensive position in this mountain region.

The exhibitions show how soldiers lived and worked in this mountain fortress, focusing on their daily routines and duties during peacetime. The displayed objects and documents provide direct insight into the regular activities of the garrison stationed at this isolated altitude.

The site is difficult to access and located at high altitude, so visitors should expect challenging terrain and cold weather conditions. The best time to visit is during warm and dry weather, when the paths are safe to navigate.

The diesel plant was not in a separate gallery but on the lower of the block's two levels, since the ouvrage has no underground network. Two SMIM 2 SR 14 two-cylinder diesels of 24 hp at 750 rpm each drove alternators, backed by a CLM 1 PJ 65 auxiliary of 8 hp at 1,000 rpm for emergency lighting and pneumatic starting. Engines were water-cooled.