The Jordanian site of Petra was probably founded in the 3rd Century BC by the Nabataeans. The city is half-built and half-carved from rock. It flourished as a trade city, controlling the movement of material, foodstuffs, and metals between Gaza, Bosra, Damascus, the Red Sea and the Persian Gulf. The city utilised a complex network of aqueducts to survive the desert environment. In 106AD Petra was absorbed into the Roman Empire and its influence quickly began to wane because of the increasing use of sea-trade and the damage sustained by the water-management system following an earthquake. The city lay dormant for a few centuries, visited only by intrepid travellers who struggled to understand how such a complex and stunning city had obviously flourished then failed. In 1812 a Swiss traveller Johann Burckhardt became the first European to visit the city. T.E Lawrence of Arabia followed in 1917. The city was proclaimed a World Heritage Site in 1985.
Petra is without doubt one of the most incredible man-made structures I have visited. This photograph shows a high altar at sunrise where human and other animal sacrifices were made. I spent two days walking around the secret city. The ruins are extensive and there are plenty of dry wadis to explore.