Anyone ever heard of the 'Marathon des Sables'?

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Grueling race:

PhotoBlog - The toughest race on earth: 150 miles across the Sahara desert

"It was absolute hell", French runner Guido Di Paola said at the end of the first day, "as one had to walk nearly the whole time. You can only run a bit downhill but you have to be very careful. But with such an incredible setting, I don’t regret coming."