The Ultra-Trail du Mont Blanc is one of the toughest ultramarathons in the world.
The trail, 166km long, takes runners up and down for a total distance of 9.4km. Starting and finishing in Chamonix, France, the race also passes through Switzerland and Italy. A maximum of 46 hours is allowed for completion.
The race's primary sponsor this year was sports-equipment company The North Face, with other sponsors including Garmin and Alcatel-Lucent.








