The stones didn’t give up their secrets easily. For decades, villagers in the dust-blown hills of China’s Loess Plateau believed that the crumbling rock walls near their homes were part of the Great Wall. It made sense. Remnants of the ancient barrier zigzag through this arid region inside the northern loop of the Yellow River, marking the frontier of Chinese rule stretching back more than 2,000 years.
But one detail was curiously out of place: Locals, and then looters, began finding in the rubble pieces of jade, some fashioned into discs and blades and scepters. Jade is not indigenous to this northernmost part of Shaanxi Province—the nearest source is almost a thousand miles away—and it was not a known feature of the Great Wall. Why was it showing up in abundance in this barren region so close to the Ordos Desert?
When a team of Chinese archaeologists came to investigate the conundrum several years ago, they began to unearth something wondrous and puzzling. The stones were not part of the Great Wall but the ruins of a magnificent fortress city...