The large carved stone sarcophagus lid is a famous piece of Classic Maya art.

The widely accepted interpretation of the lid is that Pacal is descending into Xibalba, the Maya underworld. Around the edges of the lid are glyphs representing the Sun, the Moon, Venus, and various constellations, locating this event in the nighttime sky. Below him is the Maya water god, who guards the underworld. Beneath Pakal are the "unfolded" jaws of a dragon or serpent, which Pacal is escaping from, ascending towards the World Tree (Tree of Life).