This epic race started in Chamonix, France, with 2369 runners attempting to traverse 106 miles around the Mont Blanc massif, passing through Italy, Switzerland and then back to Chamonix via multiple high alpine passes, totalling approximately 9,700 meters of ascent and 9,700 meters of descent.
The UTMB is considered to be one of the most difficult and gruelling non-stop mountain trail races in the world.