Starting at the Happy Isles trailhead, hike roughly east along the Mist Trail, turn right at Vernal Falls onto the John Muir Trail, and continue to the top of Nevada Falls. Form there, head east along the Merced River, then turn north for about a mile and a half, before splitting with the John Muir Trail and going west another two miles, which includes a steep "cable section". On top of what famous landmark are you now standing?
Half Dome