saint-julien-du-verdon, castellane, provence, france: strange geological formation beside the lake of castillon in the verdon

039 alpes alpesdehauteprovence alps ancient azur castellane castillon castllon cliff countryside daazur erosion formation france french geologic geology hiking hill lac lake landscape mountain natural nature outdoor park picturesque pine prealps provence provencealpescote ravine regional river rock rocky saintjulienduverdon slope steep strange travel tree trek trekking unusual verdon view wall