Petra is a famous archaeological site in Jordan's southwestern desert. Dating to around 300 B.C., it was the capital of the Nabatean Kingdom. Accessed via a narrow canyon called Al Siq, it contains tombs and temples carved into pink sandstone cliffs, earning its nickname, the "Rose City." Perhaps its most famous structure is 45m-high Al Khazneh, a temple with an ornate, Greek-style facade, and known as The Treasury.