In 2008, Dr. Eben Alexander contracted a rare form of bacterial meningitis that shut down parts of his brain, put him in a coma and nearly killed him. During this time, he says, he saw heaven, writing about the experience in his best-selling book, Proof of Heaven. As he came out of the coma that doctors didn't expect him to survive, Dr. Alexander says, he didn't remember who his family was. Watch as he shares the most terrifying part of his experience. Plus, hear which real-life story this reminds Oprah of in this exclusive footage you won't see anywhere else!