Yosemite is a valley of grey granite in California's Sierra Nevada, a kilometre deep and walled by some of the largest bare cliffs on Earth, with the tallest waterfall in North America pouring into it and trees three thousand years old growing at its edge. The first sight of it is from Tunnel View, at the east end of the Wawona Tunnel, where the whole valley opens at once: El Capitan on the left, Bridalveil Fall on the right, Half Dome at the far end, and the granite goes copper for a few minutes before sunset. El Capitan is a single unbroken wall 900 metres high, the most important rock face in climbing; from the meadow below you watch climbers as dots inching upward by day, and at night their headlamps glow in tents hung from the wall. Yosemite Falls drops 739 metres in three steps, and in May, when the snowmelt is running, the trail to its foot is wet with spray; by late August it has thinned to a trickle.
Half Dome is the shape on every postcard, a granite dome sliced in half, and the last 120 metres up its curved back are so steep that the park bolts two steel cables to the rock as handrails for climbers. A thousand metres above the valley floor, Glacier Point looks straight across at it, and at sunset the walls turn copper behind Half Dome and the valley lights come on one by one. South of the valley, in Mariposa Grove, the giant sequoias stand along boardwalks; the Grizzly Giant is close to three thousand years old, and one of its lower branches alone is thicker than most tree trunks. For about two weeks in late February the setting sun strikes Horsetail Fall head-on and the thin ribbon glows orange for a few minutes; the name comes from a real fire, the burning embers the park pushed off Glacier Point on summer nights for almost a century. Yosemite was set aside in 1864, the first land anywhere protected to stay wild, partly because of photographs.