Mont Blanc, the birthplace of Alpinism, backdrop to the world famous Trail Running race UTMB, 170 km loop with 10,000 m vertical gain, over 3 countries (France, Switzerland and Italy). In this Mountain race, the Athletes will battle with numerous passages in high altitude (>2500m), difficult weather conditions (night, wind, cold, rain...), testing their training and capacity of personal autonomy to the limit.