The Rocky Mountain slam is best described as an annual test of endurance, fitness, perseverance, altitude, and logistics. The idea was inspired by the Grand Slam of Ultrarunning, which has been around since the 1980s and challenges runners to complete the nation’s four oldest and most prestigious 100-milers in a calendar year.

To complete the Rocky Mountain Slam, men and women have to finish four out of five annual races in the Rockies: the Bighorn 100 in Montana in June, the Hardrock 100 in Colorado in July, the Leadville Trail 100 in Colorado in August, the Wasatch Front 100 in Utah in early September and the Bear 100 in late September. Leadville and Wasatch are also part of the Grand Slam of Ultrarunning.