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 as rope, ice axe and crampon so go prepared. "Chourum" is a local name for swallow hole and "Olympique" for the gigantic scale of the upper mouth. This arch is located by black spot at "Chourum Olympique" on IGN topographic map number 3337 west Devoluy pleat E2.

The lower entrance


At the middle of the tunnel


The upper exit


Pascal Sombardier and JMG above the gigantic mouth