ScienceDaily (Mar. 30, 2011) — Researchers from the Wildlife Conservation Society have stumbled upon a geological colossus in a remote corner of Afghanistan: a natural stone arch spanning more than 200 feet across its base. Located at the central highlands of Afghanistan, the recently discovered Hazarchishma Natural Bridge is more than 3,000 meters (nearly 10,000 feet) above sea level, making it one of the highest large natural bridges in the world. It also ranks among the largest such structures known.
http://www.sciencedaily.com/releases/2011/03/110330131350.htm