Ultra-Trail du Mont-Blanc

The Ultra-Trail du Mont-Blanc (UTMB) is a single-stage mountain ultramarathon. It follows the route of the Tour du Mont Blanc through France, Italy and Switzerland over 166 kilometres (103 miles) and a total elevation gain of around 9,600 m. It is widely regarded as one of the most difficult foot races in the world, and one of the largest with more than 2,000 starters.