What is it like to journey to hell, to go through an experience so horrific that it stays with you forever?
An unfortunate few have experienced what could be called hell on earth, and are reminded of the torment daily.
Sister Dianna Ortiz, a missionary nun, was kidnapped and tortured in Guatemala.
"Every single day, I get a glimpse of hell," the teary-eyed Sister Ortiz told ABC News.
Author Elie Wiesel survived the Holocaust, though he lost his parents and younger sister during those terrible years.
"Does hell exist?" Wiesel asked. "Of course. I believe it's here."
And Ishmael Beah was a child soldier forced into fighting the civil war in Sierra Leone.
"We were so deep into that hell … it almost seemed that nothing else existed," he said.
"I do believe that you can lose your humanity and go to some place that is dark, and … which it could be hell," Beah said. "I would have never imagined that I could be capable of doing some of the things that I was pressed into doing."
Beah was born into a quiet, simple life in the West African nation of Sierra Leone. But in 1991, everything changed. A bloody civil war broke out and crept across the countryside. Beah was only 13 years old when rebels attacked his village and slaughtered his entire family.
"I went from knowing that my family existed to the next minute knowing … all of them dying," he recalled.
Beah fled from the violence for more than a year, eventually finding a haven in a village occupied by rebel soldiers. But soon, he was given a machine gun and pressed into service as a soldier. The rebels drugged and brainwashed the boys to fight.
"It was literally kill or be killed," he said.
Beah was one of 10,000 children, some as young as 9 years old, who fought in the decade-long civil war. For motivation, the boy soldiers watched films like "First Blood," cheering every gun battle and comparing the onscreen body count to their own.
"You went out and fought, shot people, and then came back … did drugs and watched war films. You're not allowed to sit alone and think," Beah said.
"The first time you kill somebody, it's very devastating. It does something to your spirit and … you're traumatized," he said. "But then, as this goes on, it becomes normalized again. … It becomes easier as time goes on. It becomes the world, you know, it becomes the only thing that you know how to do. "
They were also forced to snort a mixture of gunpowder and cocaine known as "brown-brown" that kept them in a violent fog and numbed their guilt and pain.
Beah said it gave him "a tremendous rush of energy … and it just numbed you to everything around you. And it made looking at … atrocities that were committed … you, you thought they were funny, you know. We thought they were funny at certain times."
Beah said he no longer knew the difference between right and wrong.
"We had lost our humanity, and we had crossed … to the other side so far, you know."
Beah's descent into hell was gradual, but Sister Ortiz was plunged into hell in an instant.
"I never want to relive the moment of seeing the death of faith. The death of faith in humanity," she said. Sister Ortiz said she "lived hell."
In 1987, the Order of Saint Ursula nun moved to the war-ravaged nation of Guatemala to teach children.