Near-death experience (NDE) is a subject under the field of parapsychology. Some people which have just avoided death, during for instance surgical procedures or traffic accidents, claim to have had such experiences.
They feel, they physically leave their bodies, on the brink of death. They float towards a tunnel of light. How this “journey” is in detail, is very individual and depends on the religious belief of the subject. The experience is filled with peace and without fear.
As it is possible to revive the person, the subject feels being “called back” from this journey.
Many theories exist, what a NDE is. Some believe, it is actually a spiritual and paranormal journey. Other believe, it is all about the brain hallucinating due to the complete breakdown of body and mind.
In laboratories, it has been possible to replicate these experiences, with the use of a “Ganz-feld” around the subject. “Ganz-feld” is German, and means “Compete field” or “Encompassing field”. The subject is blinded with a sort of diving goggles, equipped with a subtle light in in them. A pair of headphones are also placed on the subject ears, emitting white noise. Some experiments involve powerful magnetic fields around the person. The subject is placed comfortably in a chair. After a while, many get the impression of entering a tunnel.
The tunnel is bright and friendly and subjects even report of “somebody” being in the room. The interesting part is, the experience is biased by the religious belief of the subject. A Christian can feel or see God or Angels. Or even a friendly Alien, if the subject believe to have seen an UFO at some time.