The concept of hell is universal and the idea of more than one hell or many hells is found in different religions and spiritual traditions. E.g. in Buddhism there are multiple Hell realms divided into both hot and cold hells. Since Buddhist believes in reincarnation these realms are only temporary as a Purgatory much like in the Catholic tradition.  

Today research of people who have been clinically dead and had so-called near death experiences confirm this belief in hell, as people have hellish experiences and agonizing life-reviews where they see painful episodes of their lives. The research of these experiences confirm the description of hell made by Pope John II in 1999 where he said that hell is a state for those who of free will “separate themselves from God.”

Is there proof of hell then? We could conclude that hell is real based on the fact that people do have unpleasant “hellish experiences” in their near death experiences. However, in an ultimate sense the reality of hell is complex.

   In her article Is There a Hell, Atwater concludes the following:

Is there a hell? To one who thinks he or she has been there, the answer is yes. To a person like myself, who has studied what evidence exists and has conducted countless interviews, the answer is this: there is more to the near-death experience than anyone currently knows. The phenomenon is vast in scope, its implications more important and more dynamic than most people are willing to admit. Heaven and hell may seem more conceptual than fact, but right now they are all we have to go on as we search further afield into what the mind and its mental imagery might reveal about the source of our being.

The fact that people do have unpleasant NDEs with hellish experiences, does count as a proof that people do have experiences of hell. However, as Atwater also tells us; hell (and heaven) may ultimately be more a conceptual reality than an actual reality. By looking deeper into the research of near death experiences and people who actually experience hell it is possible to shed a light on the complex nature of hell.