Described as the 'World's toughest foot race', the Badwater Ultramarathon spans 135 miles, starting at Badwater Basin in California's Death Valley and ending at the foot of Mt. Whitney.

If that's not tough enough consider this - The race is held annually in mid-July, when temperatures in Death Valley can exceed 120°F - in the shade!

Now in its 33rd year, the route was originally conceived as a race between the lowest and highest points of the United States: Badwater (282 ft. below sea level) and Mt. Whitney's summit (14,496ft). The original race was run by four competitors, three men and one woman, and since there was no set course they took short cuts and one even used cross-country skis to traverse the Badwater salt flats.

A few things have changed since then. While the course is now set in stone, new regulations do not allow competitive races in the John Muir Wilderness, forcing the official Badwater Ultramarathon to end at the base of Mt. Whitney. However, the route does entail climbing across three mountain ranges for a cumulative vertical ascent of over 13,000 feet.

Also, due to the large number of people who wish to participate, officials have had to restrict it to about 90 of the world's most experienced runners, picked from an application pool sent in by the athletes.

To be considered for the race, they must have previously run a Badwater Ultramarathon, completed a race organized by a member of the Badwater World Cup, or run two other races, each at least 100 miles long.

While the average completion time is about 48 hours, runners are given up to 60 hours to complete the race - They however do not receive the prestigious Badwater Belt Buckle, which besides the winners' trophies, is the only reward at the end of this grueling road race.

The 2010 race began this morning (July 12th), with the first wave of runners taking to the trails at 6.00am PST. This year's roster includes 90 endurance athletes from over 12 countries and ranges from personal trainers to students and middle school teachers. The best part is, most of them are running on behalf of their favorite charity! To read more about this event check out www.badwater.com.

Source: Wikidpedia.org, carey-goingthedistance.blogspot.com, Badwater.com, RockyMountainnews.com