Petra, Jordan - Ten Amazing Facts - as part of the travel series by GeoBeats. 10 - Inhabited by Nabataeans over 2500 years ago. 9 - City was carved into the walls of a desert canyon. 8 - The Treasury, its most famous structure, is estimated to be 2000 years old. 7 - Nabataeans prospered by controlling water supply in region. 6 - They used mechanisms like dams to store and sell water from flash floods. 5 - Spice trade further fueled Petra's prosperity in the first century BC. 4 - An earthquake in 4th century destroyed these water management systems. 3 - Change in trade routes led to Petra's eventual decline. 2 - The city was abandoned in 1189. 1 - Estimated 30,000 people lived in Petra at its peak.