World's Toughest Endurance Challenges

Not all travel is "fun in the sun" - sometimes it hurts. But that doesn't mean that it isn't fun!

A new book coming out, The World's Toughest Endurance Challenges, gives a run-down of some of the most grueling, most rewarding endurance challenges out there, across a number of different disciplines, including:

1. Triathlons and Adventure Races
2. Bike Races
3. Winter Sports
4. Marathons and Ultras
5. Swims and Boating

Let GearJunkie's writeup pique your interest, then sign up for your own endurance challenge (or at least start training!)