Running the Sahara

Follow the tracks of three accomplished marathoners: American Charlie Engle, who won a race across the Gobi Desert and another through the Amazon jungle; Canadian Ray Zahad, who has raced across part of the Sahara and Niger's Tenere Desert; and Taiwanese runner Kevin Lin, who recently won a 150-mile race across the Atacama Desert in Chile -- a trek that only half the runners entered could complete.