The concept of Le Mans is refreshingly simple: Three-person teams take turns driving one car to tally the most laps in 24 hours. The result is just about the most demanding drive on Earth. Imagine that you and two buddies jump in a car at 3 p.m. this afternoon in New York City and haul 2,800 miles to Los Angeles at triple-digit speeds, then turn around and race back to Denver before 3 p.m. the next day. Your nerves would be shot. Your mind lost in a sleep-deprived fog. And the non-stop adrenaline pulsing through your veins would be enough to make you crack. Welcome to Le Mans. "All the skills come into play: night driving, sleep deprivation, and a great understanding of the vehicle's engineering,” says A.J. Baime, author of Go Like Hell: Ford, Ferrari, and Their Battle for Speed and Glory at Le Mans. "Teams train almost the entire year for this one 24-hour race. One mistake and it could all be lost." The 83rd running begins on June 13. Here's a field guide to the fastest 24 hours in sports.