Visible from afar, this steep and rugged semi-sphere rises above Yosemite Valley. Originally named "Tis-sa-ack," a Native American expression meaning "split 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 foot of the very steep east face. They overcome this final difficulty using two steel cables attached to poles. Thanks to its unique shape, Half Dome is among America's most iconic mountains.