Underworlds refer to the mythological realms that exist beneath the surface of the earth, often associated with the afterlife. In various cultures, these places are inhabited by spirits, deities, and the souls of the deceased. For example, in Greek mythology, the underworld is known as Hades, ruled by the god of the same name, where souls are judged and sent to different areas based on their earthly lives. In addition to mythology, the term "underworld" can also describe criminal organizations or activities that operate outside the law. These underworlds are often characterized by secrecy and illicit dealings, such as drug trafficking or organized crime. The concept highlights the contrast between society's visible structures and the hidden, often dangerous, activities that occur beneath the surface.