The vanquished were enchained and thrown into Tartaros, which is as deep below the earth as the earth is below the sky. An anvil dropped from the sky falls for nine nights, and on the tenth it reaches the earth; and likewise it falls nine nights and days from the earth, and on the tenth day it reaches Tartaros.
Kerényi presents Tartarus as the cosmogonic antipode of heaven — a measurable extreme of cosmic depth functioning as the ultimate containment of the defeated Titans.
, The Gods of the Greeks, 1951thesis