HELL (hades, sheol, Gehenna): There are three words interpreted as Hell in the KJV. Hades and Sheol refer to the abode of the dead and belong to the spiritual realm. Luke 16 gives a description of Sheol (hebrew) where the righteous dead were separated from the unsaved dead by a great fixed gulf. However all of Sheol was located in the heart of the Earth. Remember though that it lies in the spiritual realm. The Rich man of Luke 16 is clearly stated as being buried in body, but his soul is in Hell, in torments. In this place, the righteous are said to be comforted while the unsaved are in fiery torments and both are aware of the other. However, Ephesians 4 and Matt 27 make clear that Christ entered the side of Sheol where the righteous dwell and emptied that place, removing the paradise of God to the third heaven. So that now, when a believer dies the bible states, "to be absent from the body is to be present with the Lord." Sheol is a temporary place of punishment which will one day deliver up its wicked dead (Rev 20) to the final "Great White Throne Judgment" of God where the books shall be opened all of the unsaved judged according to their works. These condemned are then consigned for all eternity to "The Lake of Fire" (Gehenna).
Since Gehenna (also rendered as Hell in places) replaces Sheol / Hades, it is not only a final place of punishment, but may be of a much greater degree. Also, the dead are said to be raised / resurrected to this final judgment, so that their final end in Gehenna may well be within the "Physical Realm."