Yosemite National Park and ponds, of streams, of hiking trails, and of roads. Two federally designated Wild and Scenic Rivers, the Merced and the Tuolumne, begin within Yosemite's borders and flow westward through the Sierra foothills, into the Central Valley of California. On average, about 4 million people visit the park each year, with most visitor use concentrated in the seven-square-mile (18 km) area of Yosemite Valley. Almost all of the landforms in the Yosemite area are cut from the granitic rock of the Sierra Nevada Batholith (a batholith is a large mass of intrusive igneous rock that formed deep below the surface).
Yosemite National Park valley: the Yosemite Valley Visitor Center, the adjoining Yosemite Museum, and the Nature Center at Happy Isles. There are also two National Historic Landmarks: the Sierra Club's LeConte Memorial Lodge (Yosemite's first public visitor center), and the Ahwahnee Hotel. Camp 4 was added to the National Register of Historic Places in 2003. Over of trails are available to hikers—everything from an easy stroll to a challenging mountain hike, or an overnight backpack trip. One of the most popular trails leads to the summit of Half Dome and requires an advance permit from Memorial Day weekend in late May, to Columbus