According to Greek mythology, Tartarus was the deeper of the two regions of the underworld, far below the surface of the Earth, beneath Hades itself. A place of punishment and suffering, its gates were guarded by Hecatonchires They had one hundred hands and fifty heads, and their strength surpassed that of all the Titans. There were three Hecatonchires, Briareus, Cottus, and Gyges