Kabbalah
Kabbalah combines orthodox Judaic, Neoplatonic, Gnostic, and philosophical (e.g. Aristotlean) themes, to develop an elaborate and highly symbolic cosmology in which God, who is ineffable and unknowable, manifests as ten archetypal sephirot, each with its own Divine attributes, and arranged in a configuration of interrelated paths called the Tree of Life. The original Tree gives rise to further trees, until there are four or (in Lurianic Kabbalah) five worlds or universes (Trees) in all, with the lowest sephira of the lowest world constituting the material cosmos.
This cosmology proved highly popular with occultists, and formed the basis of Western hermetic thought (e.g. the Hermetic Order of the Golden Dawn and subsequent organisations), where it is associated with a form of astral travel called "pathworking".
Read more about this topic: Esoteric Cosmology