<Tr> <Th> Reference </Th> <Td> 326 </Td> </Tr> <Tr> <Th> Inscription </Th> <Td> 1985 (9th Session) </Td> </Tr> <P> Petra (Arabic: البتراء, Al - Batrāʾ; Ancient Greek: Πέτρα), originally known to its inhabitants as Raqmu, is a historical and archaeological city in southern Jordan . Petra lies on the slope of Jabal Al - Madbah in a basin among the mountains which form the eastern flank of Arabah valley that run from the Dead Sea to the Gulf of Aqaba . Petra is believed to have been settled as early as 9,000 BC, and it was possibly established in the 4th century BC as the capital city of the Nabataean Kingdom . The Nabataeans were nomadic Arabs who invested in Petra's proximity to the trade routes by establishing it as a major regional trading hub . </P> <P> The trading business gained the Nabataeans considerable revenue and Petra became the focus of their wealth, drawing the envy of its neighbors . The earliest recorded historical reference to Petra was when the Greek Antigonids raided the city in 312 BC . The Nabataeans were, unlike their enemies, accustomed to living in the barren deserts, and were able to repel attacks by utilizing the area's mountainous terrain . They were particularly skillful in harvesting rainwater, agriculture and stone carving . Petra flourished in the 1st century AD when its famous Khazneh structure--believed to be the mausoleum of Nabataean King Aretas IV--was constructed, and its population peaked at an estimated 20,000 inhabitants . </P>

Where is the lost city of petra located