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.

Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP
Marathon des Sables 2016
Jean-Philippe Ksiazek/AFP

Defending champion Rachid El Morabity of Morocco is currently in the lead in the men's race. The top-placed woman, Natalia Sedykh of Russia, is in 10th place overall. Meghan Hicks of ultramarathon news website iRunFar said: "Not only is this year's women's race the most competitive we've yet seen at the MdS, but it could also be the most interesting in the race's 31-year history. Natalia Sedykh blew it out of the water again today, finishing 10th overall for Stage 2. I don't think a woman's ever finished in the top 10 of an MdS stage before, unless we're talking in the race's first couple years when it had very few entrants."