In historical Indo-European religion, the concept of an otherworld, also known as an otherside, is reconstructed in comparative mythology. Its name is a calque of orbis alius (Latin for "other world/side"), a term used by Lucan in his description of the Celtic Otherworld.
Comparable religious, mythological or metaphysical concepts, such as a realm of supernatural beings and a realm of the dead, are found in cultures throughout the world.[1] Spirits are thought to travel between worlds or layers of existence in such traditions, usually along an axis such as a giant tree, a tent pole, a river, a rope or mountains.[1][2][3]
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