Defying Explanation: The Mystery of the Longyou Grotto Caves

Scientists state the following five characteristics define the Longyou Grotto Caves: More than 2000 years old, man-carved, large spanned, near ground surface and medium to hard surrounding rock. To date, not a single historical record has been found mentioning the monumental construction process that involved the removal of 1,000,000 cubic meters of rock. It’s builders remain unknown to history.


One of the most mysterious underground sites ever discovered was found in the 1990’s near the village of Shiyan Beicun in Zhejiang province, China when farmers  accidentally unveiled the long-hidden underground complex.

The Longyou rock caverns are a group of extremely large ancient underground caverns. According to researchers, they were carved by hand in pelitic siltstone in the Quxian Formation of Upper Cretaceous. Upon extensive research, scientists concluded the following five characteristics defining the Longyou Grotto Caves: more than 2000 years old, man-caved, large spanned, near ground surface and medium to hard surrounding rock. The mind-boggling underground complex was unearthed by local farmers in 1992. This discovery called the attention of many specialists from numerous countries around the globe including China, Japan, Poland, Singapore, and the USA.

One of the most fascinating and challenging enigmas is why the five caverns have been able to keep their integrity for a period of over 2000 years.

Initially, the complex was thought to have been a single cave. However, further investigation showed that the cave was in fact a network of a staggering 36 underground chambers hidden below the surface. All of them carved by hand.

This extensive and rare, ancient underground ‘world’ is considered in China as the ninth wonder of the world.

But what makes the Longyou Grotto Caves so amazing?

Well, in addition to its humongous size, there is not a single ancient text that describes the underground ‘city’ nor its creation. Even today, researchers have absolutely no idea who created the impressive underground complex, what its purpose was or when it was made.

But the greater mystery is the level of precision achieved in the underground complex which occupies a staggering 2,000 square meters with the tallest point of the underground complex exceeding 30 meters in height.

The caves are notable in several respects:

  • The caves are very large considering their man-made origin: the average floor area of each cave is over a thousand square metres, with heights of up to 30 metres, and the total area covered is in excess of 30,000 square metres.
  • The ceiling, wall and pillar surfaces are all finished in the same manner, as a series of parallel bands or courses about 60 cm wide containing parallel chiselling marks set at an angle of about 60° to the axis of the course.
  • They have maintained their structural integrity and appear not to interconnect with each other.



To the amazement of researchers, the four steles of cave 1 are symmetrically distributed. The precise corners, finely carved stone and size of the underground complex has created great confusion around scientists who despite great effort, have failed to have found texts that indicate when the giant underground chambers were built or by who.

So far, researchers have only been able to conclude that the Longyou Grotto Caves are magnificent and momentous, the careful and delicate design indicates that sophisticated construction systems were used by its unknown builders. The precision present in the smallest details is indicative of superior craftsmanship which according to mainstream history should not have been possible thousands of years ago.

How is it possible that there are no historical documents that mention the mysterious underground complex? Is it possible that it was built by an unknown race? Is it possible that its construction goes back tens of thousands of years? Given the fact that the Ancient Chinese were extremely meticulous record keepers, it is a huge mystery that there are no records of the gigantic underground complex. The only thing researchers know is that the excavation of the entire complex would have been immense, as it would have involved the removal and movement of nearly 1,000,000 cubic meters of rock.

Furthermore, researchers believe that taking into account the average digging rate per day per person; it is calculated that it would have taken 1,000 people working day and night for SIX years to complete the entire project.

Commenting on the Longyou Grotto Caves , Yang Hongxun, an expert at the Archaeological Institute of Chinese Academy of Social Sciences, explained:

“At the bottom of each cave, the ancient builders wouldn’t be able to see what the others were doing in the next grotto. But the inside of each cave had to be parallel with that of the other, or else the wall would be holed through. Thus the measure apparatus should have been very advanced. There must have been some layout about the sizes, locations, and the distances between the caves beforehand.”

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  1. Very interesting. Great article. Keep on writing on these issues. Applause!

    1. Thanks! I wonder why most of these ancient underground complexes are so well tucked away. Just imagine the amount of similar sites that are yet to be discovered!?

      It is a mind-boggling ‘issue’, as to why ancient civilizations built such complex underground ‘cities’.

      1. Is it possible if ancient civilizations that were on the planet at the same time also had their own “secret societies” or their own “illuminati” that operated in total secrecy from the outside world…Building and constructing enigmatic fortresses, cave systems and languages/writings that, to common man back then, were unknown…just as they are today? Is it preposterous to think that what Chantal mentions above about underground structures being built for a purpose…not just for coming ice ages, but something more sinister to the uninitiated, were actually those civilizations’ “Area 51” and “Dulce Base” to the populace?

  2. I think all of the underground dwellings found all over this Planet were built when people saw that an ice age was coming.

    1. There is something that periodically devastates the planet and most everything living on it at the time. I believe there was at least one past civilization that understood this cycle, and left us various messages in these ruins and their placement. The key is to be found in the pyramids, I think.

      It is rather obvious that this and other engineering accomplishments were not the work of primitives.

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