Pair attempt world's hardest rock climb

Climbers on smooth Yosemite cliff chronicle effort using social media

Two men are roughly halfway through what has been called the hardest rock climb in the world: a free climb of a half-mile section of exposed granite in California's Yosemite National Park.

Tom Evans, a climber and photographer, has been chronicling Kevin Jorgeson, 30, of Santa Rosa, California, and Tommy Caldwell, 36, of Estes Park, Colorado, as they scale their way using only their hands and feet.