Built between 1930 and 1937, Fort Maginot de Rimplas was constructed to bolster the defense of the Tinée River at the bottom of the valley.
Its mission was to prevent Italian machine guns and tanks from descending from Isola.
For its exceptional scenography, Les Amis de l'Ouvrage Maginot La Frassinée was awarded the Prix Vauban 2022.