piemonte - ruins of a fortress along scenic mtb trail along ancient pathway from the alps to the sea

valle vermenagna colle di tenda fortress val roya military road ruin heritage archeology italian history stone ruins fort passo delle navette della boaria perla limone france piemonte liguria del sale europe path hiking hike wanderlust climb alps summit outdoors hill natural park maira mountain pasture italy trail bike mtb tourism trekking landscape travel summer mountains serenity cuneo maritime tranquility cottian