History’s best marathoner has broken a mythical time barrier. But it doesn’t count as a world record.
Everyone’s social nightmare might have lasting effects on relationships.
A mysterious wildcat in Sri Lanka may hold a clue.
What extreme athletes can—and can’t—tell us about human endurance
A cuddly island mystery
Personality tests have captivated people for decades, but their newfound popularity online makes them dangerous.
A familiar running trail can be a time machine.
Death has long been taboo in an American culture that values youth, but an open conversation online can increase our enjoyment of life and understanding of its eventual end.