After an early morning start (4:00am) from Chamonix the runners rise directly to the Bellachat hut (2276m) where the sun’s first rays will hit the summit of the Mont-Blanc.
After a short respite the runners will leave the top of Brevent (2525m) to descend to Planpraz (1st refreshment station).
At the heart of the Aiguille Rouges nature reserve a trail leads to La Flégère then the Chéserys chalet before descending to the Col de Montets via Tete au Vent.
The Buet hamlet (1330m) marks the beginning of a long and technical loop with an initial starter into the valley of Tré les Eaux, then a demanding climb up to the Col du Corbeau (2602m).
It is in the snow that runners will enter into the Swiss territory to climb the col de la Terrasse (2643m) after running alongside a glaciated lake.
At the heart of a mineral world the descent to the Emosson Dam requires careful attention through the final snowfields.
Soon after the pastures of La Loriaz runners can relax their muscles after over 50km of effort. The rest is short lived because after crossing Vallorcine (1260m) the ascent up the Aiguillette des Posettes tightens the calves and works the cardio.
Facing the Mont-Blanc the descent along the ridge requires runners the utmost caution when crossing the numerous steps to finally reach the village of Le Tour and then Argentiere (1260m).
To return down to Chamonix runners must take the Mont-Blanc Marathon route in reverse along the Balcon Nord in the valley.
The final challenge is the climb to the Signal (2200m) by going through one of the most well-known tourist sites in Chamonix: the Mer de Glace. A last balcony at the foot of the Aiguilles des Grands Charmoz, the Blaitiere and the Fou leads the runners to the Plan d’Aiguille hut (2200m) overlooking the Arve valley.
1200 vertical meters lower the finish line awaits the brave runners with open arms after a difficult and technical alpine journey of 80km.