Is heaven somewhere out there beyond the stars? Barbara Walters takes viewers on a heavenly journey, Tuesday, Dec. 20, on ABC. "Heaven -- Where Is It? How Do We Get There?" explores the meaning of heaven with religious leaders of the major faiths, scientists, people who say they believe in heaven because they've been there, celebrities who are vocal about their beliefs, and even with terrorists.

Walters will speak with the Dalai Lama, failed suicide bombers in Israel, an Evangelical leader, atheists, Muslim scholars, Jewish rabbis, as well as with Richard Gere, Maria Shriver, Mitch Albom and Rabbi Jackie Mason.

For centuries man has looked to the sky and asked profound questions: Where is heaven and how do we get there? People have dreamed of heaven, dedicated their lives to the promise of heaven, even martyred themselves - committing heinous acts of terrorism - for the promise of paradise. Is heaven simply a myth dreamed up to give lives meaning, or is it a real place?

Walters takes viewers on a journey around the world - to India, Israel and throughout the United States. She interviews people of different religious and scientific beliefs, each with strong opinions about the afterlife. They discuss their visions of heaven, what happens to the body, and why it is important to believe in heaven.

The special also explores:

The Science of Heaven - Why does faith come easily to some and elude others? In search of the scientific rationale of heaven, Walters talks to expert Dr. Dean Hamer, author of The God Gene, and a geneticist at the National Institutes of Health. Is there really a "God gene" that affects people's level of spirituality? The special also looks at studies of the brain itself to see if it undergoes unusual changes when someone is deep in the throes of spiritual experiences. These studies are done by Dr. Andrew Newberg, a radiologist at the University of Pennsylvania.

Near-Death Experiences - Walters also examines the phenomenon of the near-death experience. What happens when you journey to the other side of death and back? British psychologist Dr. Susan Blackmore has spent decades searching for a scientific explanation: "When the oxygen levels fall in the brain...you get massive over-activity in the brain... I think there is a true transformation, but not because you've been to heaven." But whatever the rationale, such experiences have changed many. Dr. Diane Morrissey says she felt the "white light of god" when she was electrocuted. "My near death experience changed everything about me... there is not a single experience on earth that could ever be as good as being dead," she says.

Heaven and Real People - How do you tell children what happens to their loved ones when they die? Whom do you see when you arrive in heaven? Walters talks to such people as Maria Shriver, author of a children's book on heaven, and Mitch Albom, author of The Five People You Meet in Heaven, for their take on the afterlife.