Yosemite National Park's Half Dome is a granite rock formation located at the eastern end of Yosemite Valley. The peak of the granite dome is more than 4,737 feet above the valley. In the early days it was said that the crest of the dome would never be reached by humans. Today, thousands of people venture up the cables that the Park service has attached to the backside of the dome. When they do this they reach the top of what is generally considered the highest point in Yosemite Valley. Every year people die in accidents on this slippery, steep climb.