The legendary figure known for his journey to the underworld in Greek myths is Orpheus. Orpheus, a gifted musician, ventures into the Underworld to retrieve his beloved wife, Eurydice. His enchanting music persuades Hades, the god of the underworld, to allow Eurydice to return to the living. However, Orpheus's tragic mistake of looking back causes her permanent return to the underworld, symbolizing the themes of loss and the power of love.