ANCIENT WATER COMPLEX DISCOVERED UNDER A MOUNTAIN IN CHINA!

This is an excerpt from a video I recently watched on the Universe Inside You channel. The original video is called Pre-historic mega structures in China and unexcavated pyramids.
Just had to bring this to your attention, the Longyou caves of China.
Unbelievable. Again, it's not the latest discovery, it's from 1992, but the vastness and intricacy of this complex may help to give us clues when we look across our realm at other historical mysteries!