A trail runner's fantasy, this marathon takes you to the top of one of Colorado's 14-ers, up wild and winding dirt and gravel trails. Pushing through the 7,815 vertical feet of the course (6,000 of which occur within the first 10 miles), you're rewarded with gorgeous mountain scenery and the sense of accomplishment that comes with completing an insanely challenging (or, better, straight-up insane) task. Warning: Do not expect to make good time on this course—winning times usually barely miss the four-hour mark.
Usually in: August
PikesPeakMarathon.org