Is it Ancient ruins?
https://enntourism.com/blog/mt-kono-a-planetarium-on-earth-yamazoe-nara/
A mysterious mountain stream that covered with rocks in Yamazoe Village, Nara Prefecture.
Length 650m, width 25m. Clean water flows under the rocks.
Some people think of this river as a galaxy.
According to research, there are megaliths in positions corresponding to Vega, Altair, and Deneb along this river. There is also a rock that corresponds to the North Star. However, Surprisingly, it’s not present North Star but, it was the North Star 4000 years ago.
This is Thuban. It is the same star as the North Star, which the ancient Egyptians observed in the pyramid.
Everything about underwater and sky 