Albert Lin travels to Colombia to find out the truth about the legendary city of El Dorado. He explores the ruins of Ciudad Perdida in the Sierra Nevada mountains.

Albert Lin travels to Petra, Jordan, to discover the origins of the famous city. He finds out that it was built by the Nabataeans, a mysterious civilization that learned how to survive in the desert. He tracks down evidence of their cities and temples and reveals that the ancient city of Petra was part of a much bigger network than he ever imagined.