Tartarus is the darkest and deepest area of the Underworld. Tartarus is where the gods imprison their enemies, chiefly the Titans. Kronos is known for being held there. When a monster is slain, its essence is sent to Tartarus until they can reform. Tartarus is the lowest region of the world, as far below earth as earth is from heaven. Tartarus is described as a dank, gloomy pit, surrounded by a wall of bronze, and beyond that a three-fold layer of night. According to the Illiad, it is a 9-day anvil fall from the other regions of Hades.