LES CARROZ, FRANCE (REUTERS) - One of the world's most challenging sled dog races gets underway in the French Alps.

Internationally renowned mushers and their dogs will have to travel 670km of linear track at an elevation of more than 65,000 feet over 11 days, in the La Grande Odyssee.

About 500 dogs will be racing in the challenges, with the winner to be crowned in Bonneval sur Arc on Jan 18.