Taking place in the Moroccan Sahara Desert, the Marathon des Sables is a grueling six-day trek underneath the burning sun. The 254-kilometer race is one of the most unforgiving in the world.
Marathon des Sables (Morocco) —
Taking place in the Moroccan Sahara Desert, the Marathon des Sables is a grueling six-day trek underneath the burning sun. The 254-kilometer race is one of the most unforgiving in the world.
PIERRE VERDY/AFP/AFP/Getty Images
Each competitor in the Marathon des Sables is responsible for carrying their own food, clothes and sleeping bags. The race, which started back in 1986, is run in temperatures that can reach nearly 50 C.
Sand warriors —
Each competitor in the Marathon des Sables is responsible for carrying their own food, clothes and sleeping bags. The race, which started back in 1986, is run in temperatures that can reach nearly 50 C.
PIERRE VERDY/AFP/AFP/Getty Images
It's 160 kilometers long and held in one of the world's harshest climates. The Arctic Circle Race sees competitors skiing through a snowy wilderness 65 kilometers north of the Arctic circle through temperatures as low as -30 C.
Arctic Circle Race (Greenland) —
It's 160 kilometers long and held in one of the world's harshest climates. The Arctic Circle Race sees competitors skiing through a snowy wilderness 65 kilometers north of the Arctic circle through temperatures as low as -30 C.
Klaus Sletting
Hazardous weather conditions during the three-day Arctic Circle Race can get to competitors at night, with tents their only shelter from the cold.
Cold comforts —
Hazardous weather conditions during the three-day Arctic Circle Race can get to competitors at night, with tents their only shelter from the cold.
Klaus Sletting
Held in Chile, this trekking, cycling and kayaking challenge takes place in some of the most beautiful scenery on the planet.
Patagonia Expedition Race (Chile) —
Held in Chile, this trekking, cycling and kayaking challenge takes place in some of the most beautiful scenery on the planet.
Claudio Siulva Rome
The Patagonia Expedition Race is a 10-day event that takes place in the heart of southern Chilean Patagonia. The region's capital is the city of Punta Arenas, while the closest city to the race area will be Puerto Natales.
Deep south —
The Patagonia Expedition Race is a 10-day event that takes place in the heart of southern Chilean Patagonia. The region's capital is the city of Punta Arenas, while the closest city to the race area will be Puerto Natales.
Claudio Siulva Rome
Patagonia Expedition teams must be mixed sex and made up of four people. The official race route is only released 24 hours before the start of the competition. The race takes between six and nine days to finish.
Four by four —
Patagonia Expedition teams must be mixed sex and made up of four people. The official race route is only released 24 hours before the start of the competition. The race takes between six and nine days to finish.
Walter Alvial Jara
The Iditarod Trail Invitational ultra marathon takes place in February in Alaska, in one of the harshest climates on the planet.
Iditarod Trail Invitational (Alaska) —
The Iditarod Trail Invitational ultra marathon takes place in February in Alaska, in one of the harshest climates on the planet.
Katharina Merchant
Iditarod Trail Invitational competitors can choose from a 350-mile (563-kilometer) run, ski or bike ride through the snow. For those that really want a challenge, there's the 1,000-mile (1,609-kilometer) route to Nome.
Endless ice —
Iditarod Trail Invitational competitors can choose from a 350-mile (563-kilometer) run, ski or bike ride through the snow. For those that really want a challenge, there's the 1,000-mile (1,609-kilometer) route to Nome.
Katharina Merchant
It's billed as the world's toughest jungle marathon. If the scorpions, snakes, caimans, piranhas and jaguars aren't enough, there's the 40 C temperatures and 99% humidity.
Jungle Marathon (Brazil) —
It's billed as the world's toughest jungle marathon. If the scorpions, snakes, caimans, piranhas and jaguars aren't enough, there's the 40 C temperatures and 99% humidity.
Shirley Thompson
The Jungle Marathon involves a 254-kilometer trek through swamps, mangroves and undergrowth, but there are "easier" 127- or 42-kilometer challenges.
Swamp survival —
The Jungle Marathon involves a 254-kilometer trek through swamps, mangroves and undergrowth, but there are "easier" 127- or 42-kilometer challenges.
Shirley Thompson
This prestigious ultra marathon event starts in Chamonix, France, with a route that goes through Italy and Switzerland. Each runner has 46 hours and 30 minutes to complete the 168-kilometer course.<br />
Ultra Marathon Mont Blanc (France, Italy, Switzerland) —
This prestigious ultra marathon event starts in Chamonix, France, with a route that goes through Italy and Switzerland. Each runner has 46 hours and 30 minutes to complete the 168-kilometer course.
JEAN-PIERRE CLATOT/AFP/AFP/Getty Images
Running through the night, competitors in the Ultra Marathon Mont Blanc will have to negotiate seven valleys, 71 glaciers and 400 summits -- plus 9,400 meters of altitude.<br />
High anxieties —
Running through the night, competitors in the Ultra Marathon Mont Blanc will have to negotiate seven valleys, 71 glaciers and 400 summits -- plus 9,400 meters of altitude.
JEAN-PIERRE CLATOT/AFP/AFP/Getty Images
Held in July, this race tests teams of four on the water, on foot, and on bike. There are other challenges along the way too.
Le Grand Tour (Sweden) —
Held in July, this race tests teams of four on the water, on foot, and on bike. There are other challenges along the way too.
JOHAN LUNDAHL
Le Grand Tour of Sweden's course runs 1,700 meters above sea level and takes competitors through the deep forests of Varmland. A vertical rope section, rapids, lakes and mountains are just some of the obstacles lying in wait.
Fun in the forests —
Le Grand Tour of Sweden's course runs 1,700 meters above sea level and takes competitors through the deep forests of Varmland. A vertical rope section, rapids, lakes and mountains are just some of the obstacles lying in wait.
JOHAN LUNDAHL
For the past 24 years, cycling fans have been given the opportunity to try the official Tour de France course. L'Etape du Tour, which was launched in 1993, has attracted riders from across the world.
L'Etape du Tour (France) —
For the past 24 years, cycling fans have been given the opportunity to try the official Tour de France course. L'Etape du Tour, which was launched in 1993, has attracted riders from across the world.
A.S.O.
Last year, the L'Etape du Tour amateurs rode 122 kilometers at an elevation of more than 4,000 meters. It's very popular. More than 11,000 finished the race in 2016 and places go fast.
Serious cycling —
Last year, the L'Etape du Tour amateurs rode 122 kilometers at an elevation of more than 4,000 meters. It's very popular. More than 11,000 finished the race in 2016 and places go fast.
A.S.O.