Tartarus is the darkest and deepest area of the Underworld, where the gods imprison their enemies. Tartarus is also the primordial Greek god of the abyss. Tartarus is both a deity and a place in the Underworld even lower than Hades. In ancient Orphic sources and in the mystery schools Tartarus is also the unbounded first-existing "thing" from which the Light and the cosmos is born.
Zeus asserts that Tartarus is "as far beneath Hades as heaven is high above the Earth." As a place so far from the sun and so deep in the Earth, Tartarus is hemmed in by three layers of night, which surround a bronze wall which in turn encompasses Tartarus. It is a dank and wretched pit engulfed in murky gloom. It is one of the primordial objects which sprung from Chaos, the Abyss. Along with Tartarus, Gaia (Earth), and Eros, emerged into the universe.
When the Titanomachy ended the gods of Olympus eventually defeated the Titans. Many, but not all of the Titans, were cast into Tartarus. Cronus, Epimetheus, Metis, Menoetius, and Prometheus are some Titans who were not banished to Tartarus. In Tartarus, prisoners were guarded by Hekatonkheir, giants each with 50 enormous heads and 100 strong arms. Later, when Zeus overcame the monster Typhon, the offspring of Tartarus and Gaia, he threw it, too, into the same pit and imprisoned it by trapping a mountain on top of the beast.
According to the Greek poet Hesiod, a bronze anvil falling from heaven would fall 9 days before it reached the Earth. The anvil would take nine more days to fall from Earth to Tartarus, making it approximately 4733.22 miles deep. Tartarus is described as a dark, gloomy pit, surrounded by a wall of bronze and beyond that a three-fold layer of night. It is one of the primordial objects that sprung from Chaos, along with Gaea, though some believe it was a son of Aether and Chaos, whilst Orphic sources claim Tartarus to be the unbounded first-existing entity.