Much like Norse mythology, in some of the ethnic groups of northern Siberia there is the belief in a world tree that connects all the realms of existence. The upper realms are where the good deities roam and the lower realms are where the bad deities roam. There are variously three to seven realms mentioned.
Several things all the peoples have in common is that the world tree connects all the realms, earth is the middle realm or realm of man, and shamans are the only who are able to climb up and down the world tree. Often times they can only do so when changing into an animal, though this is not necessary.
Shamans travel to and from realms to learn, fight, and gain magical powers. There are few really cool stories from Siberian myth I will relate over the coming days.