Rainbow Bridge National Monument
| Rainbow Bridge National Monument | |
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IUCN category V (protected landscape/seascape)
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| Location | San Juan County, Utah, United States |
| Nearest city | Page, Arizona |
| Coordinates | 37°04′38″N 110°57′51″W / 37.07722°N 110.96417°WCoordinates: 37°04′38″N 110°57′51″W / 37.07722°N 110.96417°W |
| Area | 160 acres (65 ha) |
| Created | May 30, 1910 |
| Visitors | 92,311 (in 2011) |
| Governing body | National Park Service |
| Website | Rainbow Bridge National Monument |
Rainbow Bridge National Monument is administered by Glen Canyon National Recreation Area, southern Utah, United States. Rainbow Bridge is often described as the world's highest natural bridge. The span of Rainbow Bridge was reported in 1974 by the Bureau of Reclamation to be 275 feet (84 m), but a laser measurement in 2007 has resulted in a span of 234 feet (71 m). At the top it is 42 feet (13 m) thick and 33 feet (10 m) wide.
Two other natural arches, Kolob Arch and Landscape Arch, both also in southern Utah, have confirmed spans several meters longer than Rainbow Bridge, but by most definitions of the terms they are considered to be arches rather than bridges. With a height of 290 feet (88 m) Rainbow Bridge does indeed stand taller than either of its longer competitors, but it is outdone by Aloba Arch in Chad at 394 feet (120 m). The world's tallest (though less easily accessible) arch is Töshük Tagh, better known as Shipton's Arch, in China at an estimated 1,200 feet (370 m). Finally, Xianren Bridge (also known as Fairy Bridge), in Guangxi Province, China, with a span of about 295 feet (90 m), and a height of the opening of 210 feet (64 m), appears to be the natural bridge with the largest span in the world.
Rainbow Bridge is one of the most accessible of the large arches of the world. It can be reached by a two-hour boat ride on Lake Powell from either of two marinas near Page, Arizona, followed by a mile-long walk from the National Park wharf in Bridge Canyon, or by hiking several days overland from a trailhead on the south side of Lake Powell (obtain a permit from the Navajo Nation in Window Rock, Arizona).
Rainbow Bridge is made from sandstone formed during the end of the Triassic and the Jurassic periods. Extreme fluctuations in climate during the Triassic and Jurassic periods—the region was alternately a sea and desert on par with the Sahara—produced layers of sandstone with different levels of hardness. By the end of the Jurassic, the sea returned to cover these layers of sandstone and compressed them so tightly that they would persist until the present day.
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Wikipedia