These two places are connected by unforgettable panoramic path along Crête d l'Ortiguier (ortie - means nettle and you can sniff there its characteristic smell). Once, this mountain's crest led to the old border and was protected by Redoute des 3 Communes. These interesting fortification was built in 1897 on the site of an ancient Sardinian battery. Small dimensions, built in height, and surrounded by a moat - the building is considered to be a prototype of concrete bunkers in the Alps Maritimes (it's first fort of Alpes-Maritimes where stonework and reinforced concrete are associated).
Redoute des 3 Communes is the culmination of the massive Authion (2080 m) and one of the former strategic points to control the valley of La Roya and Vésubie.
More informations (the sources):
http://www.maginot.org/f225/raus_fr.htm
http://wikimaginot.eu/visu.php?id=14265
http://www.cheminsdememoire.gouv.fr/fr/redoute-des-3-communes
