It's one of humankind's great unanswered questions. Type "what happens" into Google's search engine and the first phrase you're offered is: "What happens when we die."
We've all heard tales of bright lights at the end of a tunnel, or visions of dead loved ones. It might sound like something from a fantasy film, but it turns out to be a common experience.
And thanks to growing rates of successful resuscitation, we're hearing about more of these experiences. In fact, a quarter of patients who've had a cardiac arrest report having them.
Dr Natasha Tassell-Matamua at Massey University has been researching the phenomenon, and says near-death experiences positively change people.
"While there's a lot of debate about whether they're real or not, what I can say with some certainty is that the after-effects of the experiences are very much real," she told The AM Show on Tuesday.
"People will often report these overwhelmingly positive benefits from the experience.
"Some of those benefits can include that they feel a lot more compassionate towards others, they feel more tolerant of others and situations, they tend to report greater concerns with environmental issues."
She says the main effect she's seen in research is the sense of love and compassion survivors get for other human beings, and it's not restricted to people close to them.
"The near-death experience (NDE) contravenes some of our accepted norms of reality, and maybe that provides some sort of catalyst for change.
"People have argued 'maybe it's just a close brush with death' that causes these changes, and absolutely, I think any sort of significant life event does cause change.
"But there's certainly been research to suggest that when comparing people who've had an NDE and those who haven't - but both have had a close brush with death - they both experience change, but the change appears to be more profound with those who've had the NDE and it also appears to last a lot longer.
She says it suggests there is something about a near-death experience that creates such positive after-effects.
The research findings were published in Journal Of Spirituality In Mental Health.