Where did Percy and his friends get trapped?

Percy and his friends got trapped in the Labyrinth, a vast and complex underground maze created by Daedalus. As they navigated its winding passages, they encountered various challenges and monsters. The Labyrinth serves as a crucial setting in "The Battle of the Labyrinth," the fourth book in Rick Riordan's "Percy Jackson & the Olympians" series, highlighting their struggle to find a way out while facing numerous dangers.