Hades, the underworld/afterlife of Greek mythology, was portrayed as a bleak realm located at the edge of the world disc beyond the ocean at the rim of the sky. It was said to be the place where all souls went after death, regardless of their moral standing.
Hades was said to be encircled by five rivers: the River Styx that souls cross on a ferry after being received by Minos and Rhadamanthus, and the Phlegethon, Cocytus and Lethe rivers. The Gates of Hades are guarded by Cerberus, the three-headed dog. It was not until later that Tartarus, the Greek equivalent of Hell and the prison of the Titans, was introduced as a part of Hades; it was originally its own separate realm. Similarly, the Elysian Fields that were the final reward for heroic figures did not originally exist in Hades.
The chief environment in Hades was thought to be endless fields of asphodel plants, bland flowers that could be eaten as sustenance. The afterlife in Hades was an ethereal, miserable existence, with the shades of mortals in a limbo-like state between existing and not existing. Hades himself resided in a gem-encrusted palace; this was fitting, because not only was Hades the god of the underworld, he was also the god of wealth and the treasures of the earth.