In 2009, photographer Zandy Mangold's dream came true when ultra-marathon organization Racing the Planet hired him to shoot their annual 4 Deserts series; These assignments have allowed him to combine his passions for running, photography and adventure travel. The yearly series begins in Chile's Atacama Desert; heads to the Gobi Desert in northwest China, then to the Sahara in Egypt, and finishes the season in Antarctica .

Mangold has not only documented these grueling races, but also crossed over to the competitor side. This year, he competed in his second Atacama Crossing, which is considered by some to be the most challenging stage race in the world.

Sahara Desert in Egypt, 2009

Each race is at least 150 miles, and the competitors must be self-supported - they run with all of their provisions for the week in specialized racing backpacks. Water and emergency medical care are the only aid provided during the race. As a competitor, Mangold starts a race with an 18-pound pack, while as a photographer, he may haul up to 30 pounds of gear.

Atacama Desert China, 2011

American George Chmiel runs through freezing water in the Atacama Desert in Chile, 2011.

The race is divided into six stages over seven days. The first four stages are each approximately a marathon in length while the fifth stage is a double marathon-lasting well into the next morning for some competitors. The race concludes with a 10 kilometer "sprint" into the desert oasis-town of San Pedro De Atacama.

Food packs being packed at Atacama Desert campsite, 2011 The typical race diet consists of gels and electrolytes while running and a freeze-dried meal for dinner. In addition to the pre-cooked fare, Mangold spoils himself by adding a chicken boullion cube to hot water and pretending it's the most delicious soup ever. The dietary restrictions owe to the fact that the pack should be as light as possible.

Mehmet Danis of Canada won The Atacama Crossing Race, April 5, 2009.

Each race offers unique challenges. For example, in Chile, runners scramble up sand dunes, traverse crusty mud flats, and ascend and descend a network of rocky dirt trails all the while in between 9,000 feet and 13,000 feet of altitude.

Receiving emergency IV's at the end of Stage One, Australian Outback, 2010.

Mangold recalls his first and almost last race as an ultrarunner: "Back in 2010, I was curious enough to attempt a 150-mile, six stage, seven day, self-supported race through the Australian outback. While I did finish the race, I came in last place and nearly joined the kangaroo carcasses I saw along the course. At the end of just the first stage, I was administered two emergency IVs. The medical team urged me to accept a third IV, but I refused. Three IVs would have meant disqualification."

Nepal, 2011.

American George Chmiel leaps across a gulley, Gobi March, China, 2012

Darren Nichols elevates sore feet during Racing The Planet's 7 day ultra-marathon in the Atacama Desert in Chile in 2011.

Runners strung out along the snow, Antarctica 2010.

Nahila Hernandez of Mexica, China's Gobi Desert March, 2012.

Runners reflected in heat waves, Wadi Rum, Jordan, 2012.

Runner and photographer Zandy Mangold finishes the Atacama Crossing in fourth place, Chile, 2012. (Courtesy Scott Manthey/Racing the Planet)

After the frightening experience in 2010, Zandy came back stronger than ever in 2012. "In 2012, in a reversal of fate, I was the first American finisher and overall 4th place finisher in the Atacama Crossing, an event which has been deemed by some as the toughest footrace on the planet. "

Atacama Desert, Chile in 2011.

Atacama Desert Campsite, 2011

"Camping under the night sky of the Atacama is a unique experience."

Canadian dentist Ash Moktari's red shirt breaks up the sand in the Atacama Desert in Chile in 2011.

Egyptian Sand Dunes Sahara Desert 2009

A former captain of the Connecticut College cross-country team, Mangold's fitness level paid dividends on the Racing The Planet jobs when he was able to reach places along the challenging terrain that were inaccessible by even the most rugged off-road vehicles.

South African ultrarunning legend Ryan Sandes, in a rare moment of sunshine during the Racing the Planets Antarctica race, 2010.

Sahara Desert in Egypt in 2009.

Idyllic campsite during in the Sahara Desert in Egypt in 2009.

Since his first ultramarathon assignments, Zandy has also documented races in the Himalayas in Nepal, the Wadi Rum in Jordan and will photograph the first ever stage race held in Iceland, in August, 2013.

Competitors experience a wide range of emotions at the finish line of Racing The Planet's seven day self-supported race in the Gobi Desert in 2012.

Mangold started this extraordinary challenge four years ago and isn't about to quit anytime soon. "The job is exhausting, both physically and mentally," he says. "I train for the work by running with a weighted pack through the streets of New York in the months prior to the assignment in order to emulate running long distances with camera gear. In spite of these challenges, the extraordinary athletes and breathtaking vistas inspire me to keep shooting. I am grateful for the opportunity to do what I love. "

Zandy Mangold races into position during Racing the Planet's seven day self-supported ultra- marathon in the Sahara Desert in Jordan, 2012.

All Photos and Quotes by Zandy Mangold

To see all of Zandy's photos from the Atacama Crossing, visit the race gallery here.

For more Information on Ultra-Marathons Check out : RacingthePlanet and 4Deserts.com