Katabasis

The ancient Greeks and the peoples of remote antiquity already knew of journeys of the soul, but these were often journeys to the infernal regions, descents into hell, catabases, with obstacles, such as encounters with various monsters, menaces of all sorts, the crossing of the bridge of the dead or the passage of mysterious rivers on foot or on horseback.

Source: wiktionary

The logic of the underworld is most on show in the Phaedra and the Hercules [of Seneca], which feature the returns of Theseus and Hercules from their katabases.

Source: wiktionary

Willy, the concentration camp survivor who has experienced more evil than any other character, places no value on catabasis. When asked (in connection with Aeneid VI) 'Do you think everyone ought to descend to the underworld?', he replies briskly, 'Certainly not! It's very dark and stuffy and one is more likely to feel frightened than to learn anything.[…]'

Source: wiktionary

Therefore, Erling Holtsmark's point that literary-mythic katabasis captures “the imagined physical orientation of the other world relative to this one” (25), is superseded in a post-mythic, ostensibly secular worldview by a journey that takes place within an underworld that is an exteriorized 'projection' of a protagonist's putative interior world, the domain especially of the unconscious, memory and dream.

Source: wiktionary