Underworld

World of the dead in various mythologies

The underworld, also known as the netherworld or hell, is the supernatural world of the dead in various religious traditions and myths, located below the world of the living. Chthonic is the technical adjective for things of the underworld. The concept of an underworld is found in almost every civilization and "may be as old as humanity itself".

From Wikipedia, under CC BY-SA. More on occurri.