不能错过之旅

　　
　　l Imax Movie巨幕电影. Visitors to the south rim can go to the National Geographic Imax theatre outside of the park in Tusayan to see half hour presentation of "Grand Canyon, the Hidden Secrets". Showtimes are every hour on the half hour.
　　
　　l Air Tours 空中游. Fixed-wing (airplane) and Helicopter tours are offered by providers outside of the south rim in Tusayan at the Grand Canyon Airport, and also from Las Vegas, NV. Scenic flights are no longer allowed to fly below the rim within the national park. However, some helicopter flights land on the Havasupai and Hualapai Indian Reservations within Grand Canyon (outside of the park boundaries).
　　
　　l Bicycling 单车游, is only allowed on park roads. It is not allowed on rim trails or in the inner canyon. The best mountain biking can be found on the North Rim and just outside the park in the Kaibab National Forest. Rim Tours offers multiday mountain bike tours on the North Rim, and bike rentals may soon be available on the South Rim.
　　
　　l Educational Courses教育性路线. The Grand Canyon Field Institute offers short (1 to 5 day) courses at the canyon. Northern Arizona University in Flagstaff offers a Grand Canyon Semester for college credit.
　　
　　
　　Yosemite National Park 优胜美地国家公园
　　
　　Yosemite National Park is a national park largely in Mariposa County, and Tuolumne County, California, United States. The park covers an area of 1,189 mi² (3,081 km²) and stretches across the western slopes of the Sierra Nevada mountain range. Over 3 million people visit Yosemite each year, with most only seeing Yosemite Valley. Designated a World Heritage Site in 1984, Yosemite is internationally recognized for its spectacular granite cliffs, waterfalls, clear streams, Giant Sequoia groves, and biological diversity (about 89% of the park is designated wilderness area). It was also the first park set aside by the U.S. federal government and through the work of people like John Muir was a focal point in the development of the national park idea (although it was not the first designated a National Park.)
　　
　　Yosemite is one of the largest and least fragmented habitat blocks in the Sierra Nevada, and it supports a diversity of plants and animals. The park has an elevation range from 2,000 to 13,123 feet (600 to 4000 m) and contains five major vegetation zones: chaparral/oak woodland, lower montane, upper montane, subalpine and alpine. Of California's 7,000 plant species, about 50% occur in the Sierra Nevada and more than 20% within Yosemite. There is suitable habitat or documented records for more than 160 rare plants in the park, with rare local geologic formations and unique soils characterizing the restricted ranges many of these plants occupy.
　　
　　The geology of the Yosemite area is characterized by granitic rocks and remnants of older rock. About 10 million years ago, the Sierra Nevada was uplifted and then tilted to form its relatively gentle western slopes and the more dramatic eastern slopes. The uplift increased the steepness of stream and river beds, resulting in formation of deep, narrow canyons. About 1 million years ago, snow and ice accumulated, forming glaciers at the higher alpine meadows that moved down the river valleys. Ice thickness in Yosemite Valley may have reached 4,000 feet (1200 m) during the early glacial episode. The downslope movement of the ice masses cut and sculpted the U-shaped valley that attracts so many visitors to its scenic vistas today.