The military constructions of the Authion mountains were built as part of the program of General Séré de Rivières, Chief of Engineering at the French Ministry of War in a context of international tensions that followed the reunion of the County of Nice to France in 1860, then the war of 1870.
In 1877, the French army began to draw mule tracks for the yards. The track coming from Breil through Maglia valley was widened and a nice little tunnel was built between 1887 and 1894.
These works of occupation of the site were intended to prevent an opponent from seizing the massif of Authion. Each redoubt includes internal barracks for combat situations. The non-fortified barracks of Plan Caval and Cabanes Vieilles completed the accommodation in peaceful periods.
Three fortresses were completed between 1887 and 1900, on lForca peaks, Milles Fourches and finally Trois Communes.
During the 1930s, more modern Maginot structures were built in the Authion Massif to adapt the lines of defense to combat modes evolutions.