DEATH VALLEY, Calif.-- Ninety of the world's toughest athletes are expected to compete in the 30th anniversary Kiehl's Badwater Ultramarathon Monday through Wednesday, covering 135 miles from Badwater, the lowest point in Death Valley, to Whitney Portals in the Sierra Nevadas.

The runners depart Badwater, 17 miles south of the Furnace Creek Visitors Center in Death Valley National Park, in three groups at 6 a.m., 8 a.m. and 10 a.m. Monday.

It is the most demanding race anywhere on the planet, a true "challenge of the champions," race sponsors AdventureCORPS Inc. proclaim.

The course covers three mountains ranges, for a total of 13,000 feet of cumulative vertical ascent. Badwater is 280 feet below sea level. Whitney Portals, at 8,360 feet, is the trail head to the summit of Mount Whitney, the highest point in the continental U.S. Competitors will run through Death Valley National Park, which can experience high temperatures over 120 degrees this time of year.

Runners will travel on Highway 190 past Death Valley landmarks like Furnace Creek, Salt Creek, Devil's Cornfield and Stovepipe Wells, then on to Keeler and Lone Pine, Calif.

The 2007 roster includes 44 Badwater veterans and 42 rookies, athletes known for their exploits as adventure racers, mountaineers, triathletes or contestants in other extreme events. Fifteen foreign countries are represented, including Australia, Austria, Brazil, Canada, Denmark, France, Germany, Hungary, India, Jordan, Mexico, South Africa, Switzerland and the United Kingdom as well as the United States. The youngest competitor is 24, the oldest is 70.

The course record was set in 2005 by Scott Jurek of Seattle, Wash., in a time of 24 hours, 36 minutes, eight seconds. The average finishing time is roughly 48 hours. Contestants who finish in less than 48 hours receive the coveted Badwater belt buckle. There is no prize money.

Jurek, 33, the 2005 and 2006 champion, is competing again this year along with former champion Dean Karnazes, 44, of San Francisco, the 2004 winner, Marshall Ulrich, 56, of Idaho Springs, Colo., who won in 1991, 1992, 1993 and 1996 and David Jones, 55, of Eagleville, Tenn., the 1997 champion.

Kiehl's, the title sponsor, was founded as an old-world apothecary in New York City. AdventureCORPS Inc. is producing the race for the eighth year.

This year 63 of the entrants are competing on behalf of a charity of their choice. The official charity of the 2007 ultramarathon is the Challenged Athletes Foundation.

This year's race celebrates the 30th anniversary of Al Arnold's original trek from Badwater to Mount Whitney in 1977, the lowest to the highest point in the continental U.S. Arnold, an ultrarunning pioneer and human potential guru, competed in a solo effort. The official race began 10 years after his pioneer feat.

Fans can follow the race through a live web cast produced by AdventureCORPS at www.badwater.com.