THE WORLD’S TOUGHEST RACES
THE HOTTEST: Marathon des Sables
Where: In the Moroccan Sahara desert, route changing annually
How long: About 250km over six days
Terrain: Desert sand
Temperature: At night 0°C, by day 40°C
Record: 16h 27m
Water required: Nine litres daily
Risks: Disorientation. In 1994, one lost entrant was found alive – just – nine days later.
THE HIGHEST: Tenzing-Hillary Everest Marathon
Where: Up and up from Mt Everest base camp in Nepal
How long: 42.195km
Record: 3h 28m 27s
Highest point: 5,364m
Risks: Yeti sightings brought on by severe lack of oxygen.
THE WILDEST: Jungle Marathon
Where: Amazonian Brazil How long: 254km
Terrain: Jungle Temperature: 40°C
Record: 32h 18m
Humidity: 99 per cent
Risks: Leeches, anacondas, piranhas.
THE COLDEST: Polar Race
Where: Canada, from Nunavut to the magnetic North Pole
How long: 650km
Terrain: Snow and ice
Record: 10d 9h 45m
Risks: At 50 below, it’s not just the liquids you take on that freeze.