For centuries, those brought back from death's door have claimed they had a glimpse of the afterlife.
They speak of seeing a tunnel, a light, dead relatives, or their own lives flashing before their eyes.
Some even recall floating out of their body and watching doctors struggling to revive them.
Medical and scientific experts have maintained these 'near-death experiences' do not exist and are simply a normal reaction to intolerable stress.
Yet now university researchers claim to have produced compelling scientific evidence that they really do happen.
Others say this may show the mind continues to exist after death.
Near-death experiences (NDEs) occur when someone is clinically dead, their heart has stopped beating and their brain no longer functioning.
The study, one of the most extensive scientific investigations into the phenomenon, shows that almost one in five heart attack patients who were brought back to life had had an NDE.
The researchers say known medical explanations cannot account for these out-of-body sensations.
Dr Pim van Lommel and colleagues from the Rijnstate Hospital in Arnhem, Holland, investigated the experiences of 344 heart patients resuscitated after cardiac arrest.
All had been clinically dead at some point during their treatment, says a report in The Lancet today.
Sixty-two patients reported NDE, of whom 41 described a deep experience during a special state of consciousness. These included outofbody experiences, pleasant feelings, and seeing a tunnel, a light, deceased relatives, or a life review.
The researchers said: 'Our results show that medical factors cannot account for occurrence of NDE; although all patients had been clinically dead, most did not have NDE.
'If purely physiological factors caused NDE, most of our patients should have had this experience.'
Dr Sam Parnia, a clinical research fellow at Southampton University who made similar findings earlier this year, called the latest report 'very exciting'.
'This is a very significant study because it takes us one step closer to understanding the human condition at the end of life which has been ignored by the scientific community until recently,' he added.
The Dutch researchers also found that NDEs were more common among people under 60. Deeper NDE experiences were more common among women.
The experience made people believe strongly in an afterlife and removed their fear of death. Dr Parnia, who hopes to carry out further research in Britain if he can get funding, said the Dutch study shows some people have remarkably similar impressions of what happens when they are clinically dead.
'In the past it has been assumed that consciousness comes to an end when the brain stops functioning, but there may be some kind of independent existence,' he said.
'It is also significant that people who had an out-of-body experience had a lessened fear of death as a result. Previously it has been suggested that just being close to death makes people feel that way, but it was not found among those who did not have NDE.'
He added: 'The main significance of the NDE lies in the understanding of the relationship between mind and brain, which has remained a topic of debate in contemporary philosophy, psychology and neuroscience.
'Very little is known scientifically about the subjective experience of dying, the nature of the human mind and its outcome during " clinical death". The findings need to be investigated with a much larger study. If the results are replicated, it would imply that the mind may continue to exist after the death of the body, or an afterlife.'
But chartered psychologist Christopher French, from Goldsmiths College, London, said there were alternative explanations for NDEs.
'Some people may have developed a false memory based on something called imaginative inflation, where the individual actually takes on board the details of an experience as if it did happen.'http://www.dailymail.co.uk/news/article-89926/Scientists-discover-near-death-evidence.html