In the hills of Mexico, a tribe of Indians carries an ancient secret: a diet and fitness regimen that has allowed them to outrun death and disease. We set out to discover how the rest of us can catch up.

On the world’s longest footrace, which takes place entirely within Queens:

Such were the hazards last summer in Jamaica, Queens, at the tenth running of the Self-Transcendence 3,100. The fifteen participants—all but two of them disciples of the Bengali Guru Sri Chinmoy, who has resided in the neighborhood for forty years—hailed from ten countries on three continents. They ran in all weather, seven days a week, from 6:00 a.m. to midnight, or until their bodies compelled them to rest. If they logged fewer than fifty miles on a given day, they risked disqualification. By their own reckoning, the runners climbed eight meters per lap, mounting and descending a spectral Everest every week and a half. They toiled in this fashion for six to eight weeks, however long it took them to complete 5,649 circuits—3,100 miles—around a single city block.

On the plains of New Mexico, a band of elite marathoners tests a controversial theory of evolution: that humans can outrun the fastest animals on earth.

Unfortunately for International Association of Athletics Federations officials, they are faced with a question that no one has ever been able to answer: what is the ultimate difference between a man and a woman?

What runner Caster Semenya’s story reveals about gender, race, science and the politics of athletics.

On the toughest foot race in the world:

The race consists of five loops on a course that’s been officially listed at twenty miles, but is probably more like twenty-six. The moral of this slanted truth is that standard metrics are irrelevant. The moral of a lot of Barkley’s slanted truths is that standard metrics are irrelevant. The laws of physics and human tolerance have been replaced by Laz’s personal whims. Even if the race was really “only” a hundred miles, these would still be “Barkley miles.” Guys who could typically finish a hundred miles in twenty hours might not finish a single loop here. If you finish three, you’ve completed what’s known as the Fun Run. If you happen not to finish—and, let’s face it, you probably won’t—Laz will play taps to commemorate your quitting. The whole camp, shifting and dirty and tired, will listen, except for those who are asleep or too weak to notice, who won’t.