Petra is an ancient rock city, in present-day Jordan. It is known to the Arabs as Wadi Musa for the stream that flows through it. The city stands on an open plain that can be reached through a narrow, winding pass between towering walls. The plain is surrounded by hills in which tombs have been carved in the pink sandstone. The site includes some 800 structures, the best known of which is the Pharoah’s Treasury, a mausoleum, monument, or temple with a two-story facade and Hellenistic split pediment.

Petra was built around 9 BC during the reign of King Aretas IV. Its early occupants were the Edomites and the Nabataeans (an Arab tribe), who had their capital here from the 4th century BC. The Romans conquered the city in AD 106. Petra flourished during the Roman Empire. It was for many centuries the focal point of a vast caravan trade but declined with the rise of Palmyra; however, it remained a religious center of Arabia. An early seat of Christianity, it was conquered by the Muslims in the 7th century and in the 12th century was captured by the Crusaders, who built a citadel there. Petra has made it to the list of the New Seven Wonders of the World.