Rising nearly 5,000 feet above Yosemite Valley and 8,800 feet above sea level, Half Dome is a Yosemite National Park icon and a great challenge to many hikers. At least a 14-mile round trip through wilderness with an elevation gain of over 4,800 feet, this hike is not for the unprepared. Permits are required to reduce crowding – protect natural and cultural resources, and improve safety. But for those who make to the top, the view is indescribable. Photo by National Park Service.