La Tour Percée is a wonderful double arch located above Marcieu Pass on "Les Petites Roches" cliffs in the Regional Natural Park of La Chartreuse. The largest opening has 32 meters span. The arch was first reported by Pascal Sombardier, who is silhouetted under the largest opening for scale. Can you imagine these arches were totally unknow until now since they are located only 25km (17 mile) from Grenoble, a city about 400 000 peoples ? It is amazing but the answer is yes! Directions : L'Arche de la discorde... en solidarité avec son ami Pascal Sombardier, l'auteur ne souhaite plus présenter sur cette page le descriptif de l'accès à cette arche.