Day: January 3, 2014

No matter what the sport, top athletes are always looking to push themselves to their limits. This drive has led to the creation of competitive events that test human physical limits. In this slideshow, explore some of the most grueling endurance contests on Earth.

We begin with a race across an entire continent — The Race Across America, a 3,000-mile bike race from the Pacific coast of the United States to the Atlantic. Participants may race solo or in teams of two-, four- or eight-person members alternating turns riding.

All participants have 12 days to finish the race. Solo riders can expect to sleep as little as 90 minutes per day and spend more than 20 hours each day on their bikes. Hallucinations from sleep-deprivation are a serious enough concern that support crews monitor the riders.

Runners in the Marathon des Sables, which…