Petra is one of the seven wonders of the world. It is a vast, unique city carved into the sheer rock by the Nabateans and surrounded by mountains riddled with passages and gorges. The Nabateans built channels that carried water from Ain Mouse (Spring of Moses) to Petra. Petra is likely to be identified as the site of ancient Edom. Petra was featured in "Indiana Jones and the Last Crusade". At a cost of about USD$40, you can take either a horse or donkey from the entrance down the valley leading to Petra. Strongly recommended to visit.