of Mont-Louis In 2008, the citadel and the city walls of Mont-Louis were listed as part of the
Fortifications of Vauban UNESCO World Heritage Site, because of its outstanding engineering and testimony to the development of military architecture in the 17th through 19th centuries. The
Mont-Louis Solar Furnace, is the world's first
solar furnace, built in 1949, by engineer
Félix Trombe. It is open to visit for practical education on solar energy uses and technologies. The citadel has been hosting for more than half a century the
National Commando Training Center (
French Army) which trains elite French troops and some foreign ones in the usage of
commando techniques and for enduring heavy physical and mental stress in combat situations. Nevertheless, some places of the citadel, like the "Puits de Forçats", can also be visited, being accompanied by a local guide. == Notable people ==