Visible from afar, this steep, rugged half-sphere rises above Yosemite Valley. Originally named "Tis-sa-ack," a Native American expression meaning "fissured rock," it has witnessed many famous ascents. The first known ascent was by George Anderson in 1875, who drilled holes into the smooth granite to successfully conquer the rock face. Since then, hikers reach the summit each year by following a trail from the valley floor. After a strenuous climb of several hundred granite steps, they find themselves at the base of the very steep east face. They overcome this final challenge using two steel cables fixed to poles. Thanks to its unique shape, Half Dome is among America's most iconic mountains.