Hades, in Greek mythology, the realm of the dead. The name originally referred to the god of the underworld, Pluto, but it later came to refer to the underworld itself. It was pictured as guarded by Cerberus, a many-headed dog with a tail of snakes, and was separated from the land of the living by rivers. The most well-known river was the Styx, across which the dead were transported. The dead were met by 3 judges, who sent heroes to the Elysian fields, while the evil were sent to Tartarus.