On a river called Vigala which on territory of Estonia, has some very curious thing. There is a place on river surface where ideally round circle is appearing from ice. Also it is not just standing, it’s rotating with some speed.
This is how its seen from drone.
And here is a video that shows how the ice is keeps rotating:
It has not appeared now. People noticed it already somewhere back in 2004. Then each year it appears.
The diameter is roughly more than 20 meters long. What you think this is might be?