Key features of the underworld in various mythologies include concepts of judgment, afterlife experiences, and realms of punishment or reward. In Greek mythology, Hades is a complex realm where souls are assessed and assigned to various fields such as Elysium or Tartarus. Similarly, in Egyptian mythology, the underworld, or Duat, involves the weighing of hearts against a feather to determine the soul's fate. Across cultures, these underworlds serve as reflections of societal values regarding morality, justice, and the consequences of one's life actions.