Since ancient times, people have reported "near-death experiences," or NDEs, including cases where people were revived long after their hearts stopped beating.
While it sounds extraordinary, these cases are so common that researchers can actually describe "symptoms" of NDEs, which many associate with getting a glimpse at the afterlife.
Seeing a "light at the end of the tunnel" is the classic description of nearly dying.
But many patients describe knowing (or being "aware") that they are dead, feeling peaceful, seeming to rise "out" of their body, moving towards a bright light, and encountering strange beings like angels, or dead loved ones.
Incredibly, nearly every culture on the planet experiences the same feelings during NDEs, although some are interpreted differently.
For example, Americans are more likely to describe the beings they see as angels, while in India they are often referred to as messengers of death.
There are still a number of competing theories about why people experience these strange feelings, and why they're so similar around the world. But a new study has shed some light on what really happens to our bodies when we pass away.
Researchers from Stony Brook University School of Medicine in New York say they have evidence that our brains continue to work for a short time after we die.
According to their new study, which draws on interviews from many NDE survivors in North America and Europe, humans remain aware of what's happening around them even after their heart stops beating, and can even understand that they are dying.
The scientists say a patient might even be able to hear and understand when a doctor pronounces they are dead.
As lead researcher Dr. Sam Parnia told LiveScience, even after "death" many patients could perfectly describe what was happening around them.
"They'll describe watching doctors and nurses working, they'll describe having awareness of full conversations, of visual things that were going on, that would otherwise not be known to them," he said.
"If you manage to restart the heart, which is what CPR attempts to do, you'll gradually start to get the brain functioning
"The longer you're doing CPR, those brain cell death pathways are still happening - they're just happening at a slightly slower rate.
While blood stops circulating to the brain after the heart stops beating, and electrical circulation ends within seconds, the study says that it could take several hours for the brain's cells to truly die.
And despite how scary it sounds, Dr. Parnia insists there are upsides to seeing "the other side" and living to tell about it.
"What tends to happen is that people who've had these very profound experiences may come back positively transformed," he said.
"They become more altruistic, more engaged with helping others. They find a new meaning to life having had an encounter with death. But there isn't like a sudden magical enhancement of their memories. That's just Hollywood jazz."
Doctors hope that by learning more about these strange experiences, they can make resuscitation safer for patients, and help protect the brain as it's "dying."