Heaven is a place of wonder and mystery for Christians, but some people who are on the brink of death have claimed to have glimpses of God's eternal kingdom. A person even asked world-renowned evangelist Billy Graham about this, after an aunt said she saw heaven before she died.

"Maybe she was just having a hallucination. I admit I'm a bit skeptical, although my aunt was a very spiritual person who read her Bible every day," the person wrote.

In response, Graham said God does give some people glimpses of Heaven's glory just before they die, although it is very unusual. "Why does this happen? It's not a hallucination or chemical reaction in the brain (as some suggest)," Graham wrote back. "I am convinced it is instead a God-given glimpse into eternity. Through it, God is reminding those who are present—and us as well—that eternity is real, and Christ is waiting to welcome us into Heaven."

However, Graham warned that people must not be misled by stories of visions or "tunnels of light." As wondrous as these places might sound, he said that Satan is sometimes using these to trick people into doing bad things or losing their faith. "Sometimes Satan tries to imitate God's work, deceiving people into thinking they don't need to commit their lives to Christ in order to be saved. Remember: Satan 'is a liar and the father of lies' (John 8:44)," he said.

Meanwhile, Graham also knows that some people are skeptical about the reality of heaven. The best case for heaven, according to the evangelist, is that Jesus Christ rose from the dead after three days.

"Think of it this way. The only way we could know for sure that heaven exists would be for someone to die and go there—and then come back to life and tell us about it. And that's exactly what Jesus did," he said.