In 2006, Scott Jurek, one of the world's best ultramarathon runners, travelled to the remote canyons of Northern Mexico to race the best athletes from an ancient Mexican tribe. The Tarahumara have a tradition of running huge distances and they gave Jurek one of his toughest races, inspiring the best-selling book, Born To Run. Scott Jurek talked to Simon Watts in 2014.

(Photo: Scott Jurek with Tarahumara runner, Arnulfo Quimare. Credit: Luis Escobar)