The world's most extreme marathons
These conditions will blow your mind
CELEBRITY Extreme sports
Marathons are hard enough as they are, often requiring that you push your body for hours, and even days, until your lungs and legs are on fire. But for the extreme-sports minded people, a regular marathon just isn't enough. From freezing to blistering weather, highest to lowest altitudes, and terrain of all kinds, click through this gallery to see the craziest conditions people actually pay to endure.