Petra, located in Jordan, was one of the ancient wonders of the world. For centuries, it was thought to be a mythical lost city like Atlantis until a Swiss explorer rediscovered it in the 19th century. Carved entirely out of rose-colored sandstone cliffs and rocks, Petra was established in the 6th century BC by the Nabataeans and contains structures like temples, tombs, and a theater carved out of the stone cliffs.