Petra originally known to its residents as Rakmu or Rakemo is a historical and archaeological city in southern Jordan. It is

adjacent to the mountain of Jabal al-Madbah, which forms the eastern side of the Arba Valley running from the Dead

Sea to the Gulf of Aqaba in a basin surrounded by mountains. The area around Petra has been inhabited since

7000 BC, and the Nabataeans may have settled as early as the 4th century BC to become the capital of their kingdom.

Archaeological work has only discovered evidence of a Nabataean presence in the 2nd century BC, by which time

Petra had become their capital. The Nabataeans were nomadic Arabs who invested in the proximity of Petra by

establishing the incense trade routes as a major regional trading center.The trading business brought considerable revenue to the

Nabataeans, and Petra became the center of their wealth. The Nabataeans,unlike their enemies, were accustomed to living in barren deserts,

and were able to repel attacks by taking advantage of the region's mountainous terrain. They were particularly skilled in rainwater

harvesting,agriculture and stone carving. Petra flourished in the first century AD, when its famous al-Khazneh structure – believed to

be the tomb of the Nabataean king Aretus IV – was built, and its population stood at an estimated 20,000 inhabitants.