One hundred miles is a long way by any measure — by car, it's roughly the distance from Denver to Vail via I-70, with travel time dependent on road conditions and (weekend) traffic. On dirt, all bets are off on how long it takes to travel 100 miles, especially when said mode of transport is human-powered. And if you're wondering who in the world would travel 100 miles under their own physical prowess (and free will), you should probably make your way to Leadville over the next two weekends and spectate the town's signature Leadville Trail 100 mountain bike and running races, which have become known in elite endurance racers' circles as the ultimate ultra events. 

So, what's an "ultra" event and what might you expect at one? For running, anything over a marathon (26.2 miles) is technically considered an ultra race, although most ultra runs typically start at 50 kilometers (31 miles). Leadville first left its mark on the world of ultra-running in 1983, when 45 participants lined up in the dark to try and tackle the course (and its 11,000 feet of elevation gain) as it meandered through the San Isabel National Forest. Today, following roughly the same route, thousands vie for a spot in the race's annual registration lottery to test their will (and lungs, and fitness) on the trail. Thousands more descend on Leadville to take part in the event, whether in the form of waking up for pre-dawn starts (6:30 a.m. starting gun for the mountain bike race, and a 4 a.m. start for trail running racers), helping out at aid stations, or watching racers trickle in over the course of hours (up to 30 for runner) as you wander in and around downtown.

Leadville Trail 100 MTB

Saturday, August 12, 6:30 a.m., corner of 6th & Harrison Streets, Leadville.

Racers depart downtown Leadville at dawn, with the first finishers expected to cross the finish line sometime around the 6-hour mark. Awards are handed out the following day (Sunday, August 13) at 7:30 a.m., with a free kids 10k planned for noon.

Leadville Trail 100 Run

Saturday, August 19, 4 a.m., corner of 6th & Harrison Streets, Leadville.

11 aid stations are located throughout the course for anyone who wants to see some of the best endurance runners in the world for a fleeting few seconds as they fuel up. Competitors take anywhere from 16 to 30 hours to cross the finish line, if you'd rather hole up at Periodic Brewing during the bulk of the event.

More information: leadvilleraceseries.com