Kinahmi
The whirl is a made by great powers of cosmos. In the middle of disc of earth stands pillar of sky. It holds dome of sky so that dome of sky does not drop on Earth. Stars are a part of dome of sky, and while sky rotates, we see stars moving. One star does not move, it is North Star. North star is a nail that connects dome of sky to the pillar of world. The pillar of world rotates with the dome of sky. Its bottom side is standing in Arctic sea, in the middle of the Earth. The rotation of pillar causes water to form a great whirl. Tuonela is under the flat earth, but the whirl is so deep that you can go to Tuonela through it.