In this “Timelines” episode, we connect three iconic sites built during the same era: Petra’s stunning rock-cut city in Jordan, the mysterious Nazca Lines etched across Peru’s desert, and the monumental Great Wall of China. Explore how the Nabataeans engineered Petra’s hidden oasis, why the Nazca created massive geoglyphs only visible from above, and what drove dynasties to construct thousands of miles of wall across China. Discover the origins, uses, and enduring mysteries of these world wonders, and see how ancient ingenuity and ambition shaped civilizations across continents—all within a shared moment in history.