Final answer:
Percy Jackson goes to the underworld to fulfill a prophecy, reflecting the grand tradition of heroic quests featured in Greek mythology.
Step-by-step explanation:
Percy Jackson goes to the underworld to fulfill a prophecy. This journey mirrors the classic heroic quests in Greek mythology, where characters such as Achilles and Perseus embark on epic adventures. Like these ancient heroes, Percy faces great challenges and meets mythological creatures on his path. The underworld itself is a staple location in Greek tales, serving as the realm of the dead ruled by Hades, and it's a key setting for confrontations and quests in mythology.