For each, their story raises questions: Is heaven real? What does it feel like to die?
And for each, their answer -- airing Sunday on CNN's "To Heaven and Back" -- will be grounded in their experience. These are their accounts:
It was January 14, 1999, and Mary Neal, an orthopedic surgeon from Jackson Hole, Wyoming, had surprised her husband, Bill, with a week-long kayaking trip with friends in the Los Rios Region of Chile.
It had been a good trip. The couple spent the week enjoying people, the food and the culture.
But that morning, Neal's husband wasn't feeling well. So he stayed behind while she joined their friends on a section of river well known for its waterfalls and drops of 10 to 15 feet.
"When I first put (afloat) on the river, I didn't feel quite right," she said.
Neal crested at the top of the first big drop in the river. She looked down into what she later described as a bottomless pit.
Then she went over.
The front end of her boat got pinned in the rocks, submerging her in the water. The force of the current pinned her to the front deck of the boat.
Her friends began searching for her, knowing that the clock was ticking.
"Time is very important," Neal said. It determines "whether you are going to rescue somebody or recover the body."
Precious minutes ticked by. "I knew I was going to die," she said.
Neal had always worked -- worked to become a doctor, worked at her marriage of 26 years, worked at raising her four children.
But she admits she made very little time for her spiritual life.
"I did take my children to Sunday school, and I tried to incorporate spirituality into my daily life -- and then I would run out of time," she said.
Pinned in the boat and out of air, Neal started to give up.
"I really gave it all over to God, and I really said, 'Your will be done,'" she said.
At the same time, she remembers her brain doing a self-assessment exam. "I could still feel the boat. I could feel the current," she said.
On the surface above her, her friends were scrambling to try to free her.
It seemed hopeless, her friends would later say.
Then something shifted, and another rock was exposed. It was just enough for the group to shift the boat to free Neal, who was sucked out of the bottom of the boat by the current -- with her legs bending back over her knees.
"I could feel the bones breaking. I could feel the ligaments and the tissue tearing. I felt my spirit peeling away from my body, sort of like peeling two pieces of tape," Neal recounted.
As one of her friends grabbed her wrist to try to pull her out of the water, Neal realized she was outside her body watching the rescue effort.
"I could see them pull my body to the shore. I could see them start CPR," she said. "I had no pulse, and I wasn't breathing. One fellow was yelling at me to come back. ...My body was purple and bloated. My pupils were fixed and dilated."
She watched people work on her, but she felt none of it.
"When I saw my body, I actually thought 'Well, I guess I am dead. I guess I really did die,'" Neal said.
As she watched, she said she was met by "these people or these spirits" who started to guide her toward a brightly lit path toward what appeared to be a domed structure.
"It was exploding, not just with light and brilliance and color but with love," she said.
There, she spoke with the spirits. They told her it was not her time to die, that she still had a job to finish, Neal said.
One of the reasons she had to return, they told her, was because of her son Willie.
"I knew very specifically with regard to my son that he was going to die," Neal said. "We talked about how he already fulfilled his job. He'd really already done what he was meant to do."
Then she was back in her body, breathing again. Those involved estimate that Neal had been without oxygen for 30 minutes.
Her recovery would take months, but she no longer took time for granted. It is a journey she chronicled in her book "To Heaven and Back."
Each day took on a new meaning for Neal, who awoke every day wondering if it would be her son Willie's last day.
On June 21, 2009, 19-year-old Willie went out to roller ski with a friend.
He and the friend stopped on a road, near a ridge.
"Wouldn't this be an incredible last sight, if we could never see anything else," Willie told the friend.
Less than a minute later, he was hit by a car and killed.
"I am my own greatest skeptic," Neal said. "I am quite sure that I would not believe my life story had I not personally lived each and every day of it. I absolutely believe that every person can look at their life and see the hand of God."
Most miracles, Neal says, are quiet.
It's that person who calls you when you most need it, she said. It's that person who directs you to someone who changes your life.