In classic mythology, below Uranus, Gaia, and Pontus is
Tartarus, or Tartaros (Greek Τάρταρος, deep place). It is a
deep, gloomy place, a pit, or an abyss used as a dungeon of
torment and suffering that resides beneath the underworld. In
the Gorgias, Plato (c. 400 BC) wrote that souls were judged
after death and those who received punishment were sent to
Like other primal entities (such as the earth and time),
Tartarus is also a primordial force or deity...
（*Ta/rtaros), a son of Aether and Ge, and by his mother Ge
the father of the Gigantes, Typhoeus and Echidna. (Hygin.
Praef. p. 3, &c., Fab. 152 ; Hes. Theog. 821 ; Apollod.
2.1.2.) In the Iliad Tartarus is a place far below the earth,
as far below Hades as Heaven is above the earth, and closed by
iron gates. (Hom. 2.8.13 &c., 481; comp. Hes. Theog. 807.)
Later poets describe Tartarus as the place in the lower world
in which the spirits of wicked men are punished for their
crimes, and sometimes they use the name as synonymous with
Hades or the lower world in general; and pater Tartarus is
used for Pluto. (V. Fl. 4.258.) - A Dictionary of Greek and
Roman biography and mythology, William Smith, Ed.