In 1952 the Mexican archaeologist Alberto Ruz Lhuillier followed a stone stairway, deliberately filled with rubble by the ancient builders, down through the body of the Temple of the Inscriptions to a corbel vaulted burial chamber and Pakal's undisturbed sarcophagus, jade funerary mask still in place over his face. The carved stone lid covering the sarcophagus shows Pakal at the moment of death, falling backward into the skeletal, fleshless jaws of the underworld, while behind and above him rises a great cross shaped world tree crowned by a bird, with a two headed serpent bar draped across its branches, the whole scene framed by celestial and earth band symbols marking the boundary between the layers of the Maya cosmos.
The image is a statement of resurrection rather than simple death: the world tree, the same axis that connects the watery underworld, the middle world of the living and the layered heavens elsewhere in Maya cosmology, offered Pakal a path upward out of Xibalba's jaws toward apotheosis as a deified royal ancestor, following the pattern later Palenque monuments such as the Temple of the Cross group set out explicitly for his son and successor. The lid became internationally famous for a different reason in the late twentieth century, when the writer Erich von Daniken proposed, without support from any Mayanist reading of the accompanying glyphic text, that it depicted an ancient astronaut piloting a spacecraft. Maya epigraphers and iconographers reject that reading; the accompanying hieroglyphic captions identify the scene in conventional Classic Maya funerary and cosmological terms, consistent with sarcophagus and stela imagery found across the wider Maya region.