Massive underground caverns carved by hand 2,000 years ago. No historical records exist. And the removed stone was never found; baffling archaeologists.
Zhangzhugang, CC BY-SA 4.0, via Wikimedia Commons
An Accidental Discovery
On June 9, 1992, local farmers in Shiyan Beicun village decided to drain several ponds they had always known as "bottomless". After pumping out the water, they did not find the source of an endless spring, but rather the entrances to five enormous, man-made caverns. Subsequent investigation revealed a total of 24 artificial caves carved from solid siltstone, covering a total area of over 30,000 square meters (320,000 square feet).
The scale of the caverns is immense. The average floor area of each cave is over 1,000 square meters, with some reaching heights of 30 meters (98 feet). Inside are stone rooms, pillars and bridges, all carved from the native rock. Despite their proximity—some walls are only 50 centimeters thick—the caves are not interconnected. This suggests a high degree of planning and surveying accuracy by the builders. Dating of glazed clay pots found in the silt on the cavern floors places their creation around 2,000 years ago, during the Western Han Dynasty.
Unanswered Engineering Questions
The Longyou Caves present a series of deep engineering mysteries. The most significant is the complete absence of any historical record of their construction. No documents, inscriptions, or texts mention this massive undertaking. Calculations estimate that removing the nearly 1,000,000 cubic meters of rock would have required 1,000 laborers working for six years straight. Yet, there is no archaeological evidence of this workforce, and the immense volume of excavated stone has never been found.
Every surface inside the caverns—walls, ceilings, and pillars—is finished with a uniform pattern of parallel chisel marks. These courses are about 60 cm wide, with the marks set at a consistent 60-degree angle. This precision across such a vast area points to a standardized, highly organized construction technique. How the builders achieved this uniformity, and how they worked in the complete darkness deep underground, remains unknown. The caves have remained structurally sound for two millennia, surviving floods and seismic activity without collapsing. This remarkable preservation, combined with the lack of documentation, is why the Longyou Caves are a puzzle in the history of ancient engineering.
💡Fun Facts
When the first cave was drained, it was expected to be teeming with fish like other local ponds, but not a single fish was found.
All 24 caves are located within a single square kilometer.
The tool marks on every surface are so uniform they look like they could have been created by a modern machine.
Only one cave contains distinct carvings: a simple horse, fish, and bird.
An adult ticket costs approximately 85 CNY. Discounts are available for students and seniors.
Accessibility
The site involves many steps and dim lighting inside the caves. It may be challenging for visitors with mobility issues. The interior temperature is cool, around 16-18°C.
