Not surprisingly this is a tough race! The race attracts around 1400 runners and boasts an impressive 2511m climb and 1490m of descent making it one of the most challenging races in Europe.
The first 10k is relatively flat however it gets progressively harder. The race starts at Chamonix taking runners along the River Arve passing through the hamlets of Les Bois and Lavancher before reaching Argentiere at 1250m. Runners then head towards the village of Montroc and the Aiguilles Rouges Nature Reserve before reaching Planpraz at 2050m offering stunning views of the formiddable mountain.