Petra is the name of the ancient city of a people called the Nabataeans. They lived in what is now Jordan in the Middle East. Petra stood at the crossroads of a number of major trade routes. In this desert environment, access to water is crucial. The people of Petra used a network of channels and cisterns to store rain water. The city grew rich from taxing high-value commodities like spices and silk. The people of Petra could afford expensive monumental tombs carved out of the red sandstone cliffs. These still survive and are a popular destination for tourists and the setting of films like Indiana Jones and the Last Crusade. Its importance waned after the 3rd century CE when it was caught up in the wars between Rome and its eastern enemies.