In our never-ending quest to understand what happens to us after we die, humans have long seen the rare phenomenon of near-death experiences as providing some hints.
People who've had a brush with death often report seeing and experiencing life-altering events on 'the other side,' like a bright white light at the end of a long tunnel, or being reunited with lost relatives or beloved pets.
But despite the seemingly supernatural nature of these experiences, experts say that science can explain why they happen – and what's really going on.
Researchers from Manchester Metropolitan University say a third of people who have come close to death reporting having experienced one - but we still don't know what causes them
Researchers from the University of Liege in Belgium collected and analysed written accounts from 154 people who had gone through a near death experience.
Their analysis showed that each person experienced around four different phenomena during their experience.
The most frequently reported features were feeling of peacefulness (80 per cent of participants), seeing a bright light (69 per cent) and encountering with spirits/people (64 per cent).
In contrast, the two most uncommon experiences were speeding thoughts (five per cent) and precognitive visions (four per cent).
A near-death experience is a profound psychological event with mystical elements.
It typically occurs in people close to death, or during situations of intense physical or emotional pain, but may also happen after heart attacks or traumatic brain injuries, or even during meditation and syncope (loss of consciousness due to a fall in blood pressure).
They're surprisingly common, with a third of people who have come close to death reporting having experienced one.
Common characteristics people report are feelings of contentment, psychic detachment from the body (such as out-of-body experiences), rapid movement through a long dark tunnel, and entering a bright light.
Culture and age may also influence the kind of near-death experience people have. For example, many Indians report meeting the Hindu king of the dead, Yamraj, while Americans often claim to have met Jesus.
Children typically describe encountering friends and teachers 'in the light'.
Most reported near-death experiences are positive, and have even helped in reducing death anxiety, affirming life, and increasing well-being.
However, some near-death experiences are negative and include feelings such as lack of control, awareness of nonexistence, hellish imagery, or perceived judgement from a higher being.
Neuroscientists Olaf Blanke and Sebastian Dieguez have proposed two types of near-death experiences.
Type one, which is associated with the brain's left hemisphere, features an altered sense of time and impressions of flying.
Type two, involving the right hemisphere, is characterised by seeing or communicating with spirits, and hearing voices, sounds and music.
While it's unclear why there are different types of near-death experiences, the different interactions between brain regions produce these distinct experiences.
The temporal lobes also play an important role in near-death experiences.
This area of the brain is involved with processing sensory information and memory, so abnormal activity in