Simply put, the nation’s toughest — and highest — marathon. The Life Time Leadville Trail Marathon and Heavy Half presented by La Sportiva takes trail runners through the historic mining district’s challenging trails to the highest point of any Leadville Race Series event: Mosquito Pass (13,185 feet). As you take on the baddest trails and thinnest air in all of endurance racing, you’ll need all the grit, guts and determination you can muster.