The toughest race in the world is currently under way in the Sahara Desert of southern Morocco. Around 1,100 runners from all over the world are competing in the Marathon des Sables – a six-day, 257km (160mi) ultramarathon through a formidable landscape, while carrying heavy survival gear, in temperatures than can reach 50C (120F). The distance is the equivalent of six regular marathons.
Runners carry all the gear they will need for the duration of the race apart from water which is supplied by the organisers. According to the race website, the Marathon des Sables needs 120,000 litres of mineral water, 300 tents, 57 medical staff, 6.5km of plasters, 6,000 painkillers ... and a touch of madness.