"A journey to the world under-ground" by Ludvig Holberg is a satirical science-fiction novel published in 1741. When philosophy student Niels Klim investigates a mysterious cave in Bergen, he falls into an underground realm orbiting an inner sun. There he encounters walking, talking trees and other extraordinary beings in the utopian state of Potu. Through his adventures across this strange world, Klim experiences diverse societies that challenge his assumptions about morality, gender equality, religion, and government. (This is an automatically generated summary.)