In the spring of 1994, Mauro Prosperi took part in a grueling six-day race called the Marathon of the Sands. Mauro, along with 133 other runners, set out to race 151 miles (234 km) across the hot and sandy Sahara Desert. On the fourth day of the race, a sandstorm struck Millions of grains of sand whirled in the air, pounding and stinging Mauro's skin. For six hours, the fierce sandstorm made it almost impossible to see. After the storm ended, Mauro...