A high-altitude redoubt built between 1890 and 1902 as part of the Séré de Rivières fortification system and then reinforced between 1936 and 1940, it played a major part in the Battle for the Alps in June 1940 due to its strategic frontier position.
All year round, daily.
Winter season: accessible via the "Espace San Bernardo" ski area
Summer season: accessible to hikers and mountain bikers, subject to weather conditions.
Spring/ autumn: ask in the Tourist Office.
Free of charge.