How common is a vertical many-layered cosmos in world mythology? Do any mythologies particularly emphasize this structure?

Question

Background: A very common motif in mythology and folklore is for worlds to be layered one on top of each other. The most obvious example is of the three world system of hell, earth, and heaven. The former and later are sometimes also given many distinct sublayers.

I'm interested in the idea of a vertical multi-layered cosmos as a theme (and I mean as opposed and mostly to the exclusion of other structures like wheels, trees, parallel dimensions, dualistic worlds, etc.). While layers often imply hierarchy, I'd also be especially keen on cases where the layers aren't straightforward hells/underworlds or heavens, that is places of punishment and reward, but are just worlds, whether better or worse.

Questions:

1) Are there particular mythologies that really emphasize this theme, such as by including many distinct layers, describing vertical travel from one layer to another, etc.

2) If so, do these mythologies tend to have other traits in common?

Thanks for your time.

Answer 1

This is only a partial answer concerning Arctic mythologies:

According to Bogoras (1907), the Chukchee's cosmogonical beliefs include the idea of a multilayered world, the North Star being the passage between them (see this previous question/answer of mine):

COSMOGONICAL BELIEFS.- According to the cosmogonical beliefs of the Chukchee, there are several worlds situated one above another, in such a manner that the ground of one forms the sky of the one below. The number of these worlds is stated as five, seven, or nine. These worlds are arranged symmetrically above and below the earth, each of the lower worlds having a corresponding one above it.
According to a statement in the tale of "The Scabby Shaman" which gives many curious details of the subject, there are four large worlds besides the earth. Those nearest to the earth are occupied by ke'let; the next, by men. In the upper and lower worlds there are the same number of animals on the land, birds in the air, and fish in the sea, so that the amount of life is the same above and below the earth.
According to other statements, the lowest world is occupied by those who have died twice, and therefore cannot return to earth. Some of these worlds have several suns, the number of which varies from two to eight. When it is winter in our world, it is summer in the next, and vice versa. [...]
These worlds are not very far apart. In the tale of "The Shaman with Warts", a shaman, while struggling with his rival, is hurled through two worlds, piercing the heaven of one head foremost, and that of the next feet foremost; then he lands in the third world on the moving ground of the clouds.
[...]
All these worlds, as said before, are joined by holes situated under the Polar Star. Shamans and spirits while going from one world to another slip through these holes.

More details can be found in Bogoras (1902), which contain for instance the complete tale of the "Scabby Shaman" referenced in the upper text.

Similarly Jochelson (1904) reported that the Koryaks believed that the

universe consists of a series of five worlds, one above the other, the middle one being our earth.

The only mention of the other worlds however is that the Supreme Being lives with his family in the Upper World.

So it seems at the very least that the conception of a multilayered world was common to the indigenous Arctic populations of the Eurasian continent. However I can not find any reference (apart from an Underworld where the deads end up) of this concept in north American Arctic populations.

Answer 2

The Lokas in Hinduism are one such. However, there is one problem: Hindu Mythology came from different timeperiods. So, there are multiple explanations for, or versions of, the same thing.

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In one version, there is the very simple system of H-E-H, with the Realm of the Gods being Swarga, the Realm of Humans as Prithvi/Dharti/OtherEarthSynonym, and the Realm of Demons as Narka/Naraka.

However, even in this theme, there is not much mention of Hierarchy. They are more like Three adjacent kingdoms, with the Gods and Demons fighting regularly, and Earth as neutral.

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In another, more complicated, and in my opinion, better, version, there are multiple layers. As in, a large amount.

• At first, on top, we have Vaikuntha, the Realm of Vishnu, 'Where one is free of all desires.'
• Then we have Sataloka, the Realm of Truth.
• There are six others, whose names or qualities I do not remember, but are related with other virtues.
• Then, on top of the highest layer of clouds, is Swarga, the Realm of Indra, 'Where all desires are fulfilled.'
• In between is Earth/Dharti/Prithvi.
• Below the surface of the Earth is Nagaloka, the Realm of Snakes.
• Then comes Patala, the Abode of Demons, where all Asuras, Rakshasas, etc. live.
• Then we have Narka/Naraka, where go the souls of the damned. Here are many divisions. In addition to the temporary-stay-torment-only normal hells, there is the Pitr, where dead ancestors are hung upside down until rebirth. There are some versions with 9 Hells, some with as many as 28. Here is also the abode of Yama.
• Below the Cosmos is the Ocean.

{I have to travel right now, so I can not add links. I would be grateful if someone did.}

Answer 3

I guess that except for many=3 such cosmoi are rare. Mythology is usually a way to explain and the three kinds "better", "same", "worse" exhaust the classes of possible qualities. If a world is not just a place but something really different, for many>3 there should be a rather complicated story to tell. Going from one place to an other is what we call travel, so cosmic travels are rather unlilkely.