A coral reef is made of thin layers of calcium carbonate A coral reef is made of thin layers of calcium carbonate National Ocean Service National Oceanic and Atmospheric Administration U.S. Department of Commerce
Arches is located in northeastern Utah, near the city of Moab. The park is famous for over 2,000 natural stone arches and offers much to the outdoor traveler. There is a 40-mile paved loop tour of the park with numerous trailheads and outlooks.
Fairy Bridge or Xianren Bridge, China. Xianren Bridge, also known as Fairy Bridge, is the world's largest natural arch with a span measuring 400 feet or 120 meter. The bridge is carved through the limestone karst by the Buliu River. It is located about 40 km northwest of Fengshan in northwestern Guangxi Province, China.