The Greeks buried their dead with coins over their eyes or under their tongues so that they could pay Charon, the ferryman, to carry them over the river Styx into the Underworld.  There they began their existence as Shades - dark, fading echoes of the living people they once were.

   There were many parts of the Underworld, The Elysian Fields, Erebus, Tartarus.  The Elysian Fields were a quiet and peaceful place of plenty where the pious and good spent their afterlife.  Erebus was the solemn realm where Shades wandered silently until they forgot all that they were and had been.  Tartarus was reserved for the worst of the dead – heretics, blasphemers and of course, the imprisoned elder gods, the Titans.