SAN FRANCISCO (AP) — 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. El Capitan, the largest monolith of granite in the world, rises more than 3,000 feet above the Yosemite Valley floor.