One of Yosemite National Park's most familiar sights is Half Dome, a granite dome rising nearly 5,000 feet above the valley floor. In 1865, the California Geological Survey declared the dome "perfectly inaccessible, being probably the only one of the prominent points about the Yosemite which never has been, and never will be, trodden by human foot." Ten years later, George G. Anderson reached the summit and in the process, laid the predecessor to today's cable route. Today, thousands of Yosemite hikers reach the top each year by following a strenuous trail from the Valley floor.

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