Tartarus

Tartarus or Tartaros is the deep abyss in ancient Greek mythology that is used as a dungeon of torment and suffering for the wicked. A part of the underworld and, in turn, below Uranus (sky), Gaia (earth), and Pontus (sea), Tartarus is the place where souls were judged after death and where the wicked received punishment.

Tartarus was used as a prison for the worst of villains, including Cronus and the other Titans who were thrown in by Zeus. Uranus also threw his own children into Tartarus because he feared they might overthrow him. These mishaps included the "Hundred-Handed-Ones", the "Cyclopes" and the "Giants".