Cross Breeds

What do you think is the most grueling race, of any type?

I'm open to any style of racing, motorsports, cycling, running, dog sledding, triathalon. Anything.

Public Comments

1. Tour De France
2. 24 hours of Lemans.
3. Ironman Triathlon. 5 mile swim, 114 mile bike, then run a full 26.2 mile marathon. And finish in under 18 hours.