The Seven Lost Cities Of The World: Petra, Jordan
Admired for its intricate rock cut architecture and advanced water conduit system, Petra is a historical marvel dating back to the 6th century BC. It was the capital city of the Nabataeans, center of trade routes and used by the civilization to control the water supply in the desert city, and was built on the slope of Mount Hor.
It was first discovered in 1812 by Swiss explorer Johann Ludwig Burckhardt. Oh, and you might recognize this lost city from a little movie called Indiana Jones and the Last Crusade.