What is the UTMB World Series? UTMB World Series – Meet your extraordinary! THE ULTIMATE GLOBAL TRAIL RUNNING WORLD SERIES Bringing together 41 leading international events across 23 countries in Asia, Oceania, Africa, Europe, and the Americas for 2024, the UTMB® World Series gives you the chance to experience the UTMB adventure close to home and to begin your quest to Dacia UTMB Mont-Blanc.