According to the program "Gates of Hell" on the History Channel, different societies have believed that the entrance to hell's here on earth -- emphasizing on the three-tier belief adopted by Christianity that Heaven's above us (sky), earth's where we live and hell's underneath us (magma, center of earth).
One thing that emphasized on this two-hour program's that Christianity's based lots of its traditions (scaring, converting people, etc) in the concept of damnation (fire, punishment in the flesh, eternal suffering, etc; yet psychological torture hardly mentioned).
I've got no doubt that hell exists. I believe that I've gone through the horror of hell many times in my life and come back just to feel them many times again (http://project05952381.blogspot.com/2010/09/as-my-soul-ran-away-at-night-every.html).
Nonetheless I don't think it's a place underneath the earth's crust. I believe that it's a spiritual place where souls are tortured.
