Just beyond Temple XIII is the Temple of the Inscriptions, a 24-meter-high (79-foot) pyramid and Palenque’s most famous structure. Its name derives from the magnificent glyph-covered tablets found in the spacious temple at its summit, which tell the ancestral history of Palenque’s rulers.

It was toward the rear of that lofty gallery that Mexican archaeologist Alberto Ruz L’Huillier first uncovered, in 1949, a secret stairway cleverly hidden under a stone slab. The stairs were intentionally jammed with rubble and debris, clearly to prevent access to whatever lay beneath.

It took Ruz three years to excavate the stairway, which descended in several sections all the way to ground level. At the foot of the stairs Ruz found another sealed passage, in front of which were clay dishes filled with red pigment, jade earplugs, beads, a large oblong pearl, and the skeletons of six sacrificial victims. A final large stone door was removed, and on June 15, 1952, Ruz made what many consider to be the greatest discovery of Maya archaeology: the untouched crypt of Pakal the Great, or K’inich Janaab Pakal, Palenque’s most decorated leader.

The centerpiece of the chamber is the massive sarcophagus, hewn from a single stone and topped by a flat four-meter-long (13-foot) five-ton slab of stone. The slab is beautifully carved with the figure of Pakal in death, surrounded by monsters, serpents, sun and shell signs, and many more glyphs that recount death and its passage. The walls of the chamber are decorated with various gods, from which scientists have deduced a tremendous amount about the Palencanos’ theology.

Working slowly to preserve everything in its pristine state, Ruz didn’t open the lid of the sarcophagus for six months. It then took a week of difficult work in the stifling, dust-choked room to finally lift the five-ton slab. On November 28, 1952, the scientists had their first peek inside. In the large rectangular sarcophagus they found another, body-shaped sarcophagus, within which was Pakal’s skeleton, with precious jewelry and special accoutrements to accompany him on his journey into the next world. A jade mosaic mask covered the face, under which his teeth had been painted red. (The mask was exhibited at the Museo Nacional de Antropología in Mexico City until December 24, 1985, when it was stolen along with several other precious historical artifacts. The mask was recovered in an abandoned house in Acapulco in 1989, mostly undamaged.)

The excavation of the Temple of the Inscriptions forced a revision of archaeologists’ conception and understanding of the ancient Maya. It was long believed that the pyramids had served a single function: to provide a platform for ceremonial temples and rituals to be closer to the heavens. But the discovery of Pakal’s tomb revealed that pyramids were used as tombs for revered leaders as well, and numerous other such temple-crypts have since been discovered.

The Temple of the Inscriptions and the passageway to Pakal’s tomb have been closed for several years; erosion caused by hundreds of thousands of visitors had become increasingly severe. In fact, access to major structures has been restricted at many Maya sites, including Uxmal, Chichén Itzá, and Tulum, with no sign of reopening any time soon.