Guan Luo Yin 觀落陰 is a practice of wu shamanism 巫術 found primarily in the South Pacific. While methodologies will differ, one approach is as an astral journey to the underworld to see the spirits of those who have passed on; another is as a method of “remote viewing.”
Some traditions conceptualize the descent as beginning from the entrance to a cave at the base of a mountain (associated with the Kunlun Mountain). Others conceptualize it as a palace with many floors descending (as opposed to ascending the way floors of a building are constructed in the physical earthly world).
This video serves as an introduction to the practice.
See also:
benebell wen 