This spectacular natural tunnel about 90 meters long is located between peaks of Grand Ferrand and Petit Ferrand on the top of Vallon du Grand Villard at 2500 meters above sea level, Hautes-Alpes department of France. Crossing this inclined natural tunnel across a cliffbare require mantle of snow to ascend the slope inside. Visitor can be found ice on the vertical wall located at the exit. Visit this challenging arch require 9 hours round trip and mountaineering material like rope, ice axe and crampon so go prepared. Chourum is a local name for sinkhole and "Olympique" for the gigantic scale of the upper mouth. This arch is located by black dot at "Chourum Olympique" on IGN topographic map number 3337 west Devoluy (pleat E2).

The lower entrance




Pascal Sombardier and Jean-Michel Genève above the gigantic mouth