The Fier is a river that flows through Haute-Savoie and Savoie into the Rhône. Near Annecy, it has created a narrow canyon that is worth a look: The so called Gorges du Fier. The Castle of Montrottier is a medieval castle not far above the canyon, built to safeguard the crossing of the river.
Above, on the way, coming from Annecy.
Above, the walkway that goes inside the gorges.
Above, the castle of Montrottier.