The “Le pietre del Lys” (the stones of the Lys) geological trail is situated in Fontainemore, in the valley basin, just a stone’s throw from the town, near the Niana green area. The feature, which is a didactic trail amid large rocky masses that illustrate the main geological events which took place in the Lys Valley, has both recreational and educational functions, making it suitable for adult visitors and children alike. The sequence of rocks accompanies visitors along a journey in the imagination which, from the Valley of the Dora Baltea goes as far as the Monte Rosa massif. The lithologies shown belong the the geological systems of the Vallaise: Austrian-Alpine system, Piedmont area, Pennidic system. The masses, of which there are a dozen gathered together in stations, mainly come from detritus deposits, stone quarries, stone landfills and banks of river beds. They come in different sizes (on average volumes in the range of 1 cubic metre) and curious rounded or smoothed shapes due to the fluvial or glacial action or sharp edges, deriving from the quarry extraction or collapses. Along the trail, visitors will find exhaustive panels featuring the main characteristics of the different rocks.