Mystery of the Longyou Caves

Inside the Longyou Grotto caves in China.
The Longyou Grotto Caves in the Yazhou region of China form an extensive, magnificent, and rare ancient underground world. (Image: Zhangzhugang via Wikimedia Commons)

Near a small village called Shiyanbei in the Yazhou region, which sits in the middle of Zhejiang Province, China, is the Longyou Caves, a cave system like no other. Its extensive, magnificent, and rare ancient underground world is considered in China to be “the ninth wonder of the ancient world.”

The Longyou Caves are thought to date back at least 2,000 years and represent one of the largest underground excavations of ancient times. Scientists from around the world are at a loss as to why these were made, or even who made them.

The strangest thing about this discovery is not so much their immense size, but the fact that there are no records existing of their creation. Here’s what we do know.

The discovery of the Longyou Caves

A villager named Grandma Wu, along with three other unnamed villagers, made the incredible discovery on June 9, 1992. After accidentally unveiling the mysterious long-hidden cave on Phoenix Hill, the villagers used four pumps to remove the water that filled the system.

After 17 days of continuous pumping, the Longyou Caves were ready to be explored. Grandma Wu was the first person to enter the mysterious underground world in a very long time. What they saw simply amazed them; however, it also left them, and others to come, confused.

Simply amazing

Although the carved out caves have gone through numerous floods and all sorts of calamities over such a long period, where even the mountains would have changed their appearance as exposed stones were weathered away, the shape, patterns, and marks inside the caves remain fresh, as if they were made yesterday.

As you walk in, you see pillars evenly distributed throughout the cave, which are supporting the ceiling and walls. As you look even closer, you can see that the ceiling and stone columns are uniformly decorated with chisel marks in a series of parallel lines. Then you notice the stone carvings depicting a horse, fish, and a bird.

After descending around 98 feet underground, you find stone rooms, bridges, gutters, and pools. The main grotto occupies more than 21,500 square feet of floor space, and at its tallest point, it exceeds 98 feet and resembles a grand hall.

Carved into solid siltstone (a homogeneous medium-hard rock), the 36 grottoes that have now been discovered cover a massive area of nearly 325,000 square feet, and all share the same characteristics.

The sheer scale of the Longyou Caves is magnificent and momentous. The design is delicate and the construction is quite sophisticated. All the grottoes that have been uncovered so far have maintained their structural integrity. They appear not to be interconnecting with each other and show the precision needed is indicative of superior craftsmanship.

How were they constructed?

It is still unclear how they were constructed; however, scientists have estimated that the workload involved in building the caves that have been uncovered is awe-inspiring.

The quantity of rock and rubble that had to be removed in the excavation of the grottoes is estimated to be nearly 35,000,000 cubic feet. Strangely, there is no archaeological evidence revealing where that quantity of rock and rubble ended up.

After taking into account the average digging rate of a person, scientists have calculated that it would have taken 1,000 people working day and night for six years to complete the caves. These calculations are based on hard labor, and do not include the sculptors’ incredible care and precision; if this was also included, it would surpass the theoretical estimation.

As for what tools were used, this is still unknown. No tools have ever been found in the area. It is also still unknown how they managed to achieve such symmetry, precision, and similarity between the different caves.

Every single one of the caves’ surfaces is virtually covered in parallel chiseled marks. This would have required immense manpower and endless hours to create, giving a uniform pattern throughout the caves.

Strange lack of fish

In southern China, most villages have very deep ponds, which are called “bottomless ponds” by many generations of villagers; these ponds are teeming with fish. When Grandma Wu and her three companions found the first cave, it was filled with water, which presumably had been there for a long period of time.

However, when Grandma Wu and her three companions pumped dry their discovery to ensure it was not just another one of the “bottomless ponds” found within the area, but a man-made structure, not a single fish was seen, or any other sign of life.

Who built them?

Short answer — nobody knows, although only the emperor and his leaders could have organized such a huge project, that’s if it was made at that time. Even if this was true, a project of this scale being commissioned by an emperor would leave historical records of its construction.

Most agree that it would have been impossible and not logical for such a job to have been undertaken by regular village people; only an emperor would have had the digging capacity.

Without knowing the purpose of the grottoes, it is hard to see regular village people spending so much manpower on creating them. Therefore, the Longyou Caves were not the product of the poor dug out of leisure and for enjoyment.

What the records say, or rather don’t say

Despite their size and the effort involved in creating them, no documents have ever been discovered that record the construction or even the purpose of the Longyou Caves. This is especially odd considering the ancient Chinese were meticulous record-keepers.

A carved pillar in the Longyou Grotto caves in China.
Despite their size and the effort involved in creating them, no documents have ever been discovered that record the construction or even the purpose of the Longyou Caves. (Image: Li Chengyun via Dreamstime)

However, records of the human studies of Longyou did not start until the Han Dynasty; therefore, there are no traceable records before this time.

Using historic information from the Zhou and Qin dynasties, and documents from the Tang Dynasty, Han Yu wrote Monument to the Xuyuan Emperor. In it, there was a record showing how “to make the room by chiseling to set a memorial temple for Emperor Yuan.”

Emperor Yuan was the fifth emperor in the West Zhou (11th century B.C. to 77 B.C.). There is no record of how big the “room” was. Using “chiseling the stone to make the room,” and then associating it with the Longyou Caves is very questionable.

So what were they used for?

After many investigations and studies, scientists and scholars alike have made attempts to explain the grottoes. However, all attempts have failed to provide convincing explanations for why they were built or what they were used for.

Some archaeologists have theorized that the grottoes were the tombs of old emperors, emperor halls, or even places for storage. But no funeral objects or tombs, not even artifacts, have been found, so this seems a little far-fetched.

The grottoes would have been designed very differently if they were used like an emperor’s palace. They would have had separate rooms for different purposes, like entertaining, meeting, and sleeping. However, there has been no evidence found of this, and there have been no traces of habitation.

Being used for mining and extracting some type of mineral resource is yet another hypothesis. But if it were a mining operation, then equipment to extract the rocks and transport them would have been required.

As before, there have been no traces of this, nor has there been any evidence of where the rocks were taken. They offer no explanation as to why there were such intricate decorations on the walls, columns, and ceilings if these were just a mine.

Some have also suggested that the grottoes were built for troops to be stationed in. This is because emperors from the past wanted to keep their soldiers out of view in order to keep their war preparations a secret. This seems unlikely, as these caves could not have been built in a short period of time. Furthermore, there are no signs of people having ever stayed in the caves.

What now?

Despite decades of research, very few answers have emerged to explain the enigma of the Longyou Caves. However, while the origin of the caves is still unknown, the caves have been opened for tourists who are willing to make the trek to the remote village. Here are some of their reviews:

“A large group of us toured on a rainy day. You start the tour with a short film, which is very helpful. Make sure you wear comfortable non-slick shoes. There are several steps. Some areas require quite a bit of energy to climb. The Grottoes are beautiful.”

“Even after reading reviews, I was still really unsure what to expect from here. So when we stepped into the first cavern we entered (#7, I believe?), I was happily surprised to feel a sense of awe.”

The Longyou Caves are an immeasurable mystery to the world, with some even saying they can be compared to the pyramids in Egypt.

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