Mont-Louis (Catalan: Montlluís or el Vilar d'Ovansa) is a commune in the Pyrénées-Orientales department in southern France.
In 2008, the citadel and the city walls of Mont-Louis were listed as a UNESCO World Heritage Sites, as part of the "Fortifications of Vauban" group.
The Mont-Louis Solar Furnace, is the world's first solar furnace, built in 1949, by engineer Felix Trombe. It is open to visit for practical education on solar energy uses and technologies.
The Mont-Louis Solar Furnace is an experimental solar furnace - a solar thermal energy facility that was built in 1949. It was the first facility of its kind in the world, and was a precursor of the Odeillo Solar Furnace. It provides a thermal power of 50 kW.