What is Xibalba?

Xibalba, also known as the Underworld, is a representation of humanity's imagination and fear. It is mentioned numerous times that Xibalba and the gods that reside in it are created from the minds of humans. Their fear builds swamps and deserts with deadly monsters. Their imagination creates grand castles and beautiful lakes. It shows a duality between the living and the dead, humans and gods, and how one cannot live without the other.