Railroad workers found a 1,000-year-old altar—surrounded by human skulls

Here’s what you’ll learn as you read this story:

• Crews working to expand a passenger rail line in Mexico discovered a 1,000-year-old sacrificial altar.

• Excavations of the three-tiered stone monument yielded four skulls and several femurs.

• Artifacts associated with the altar are probably associated with the palace at the site.

Passengers traveling on the planned Mexico City to Querétaro rail line will likely pass by the Tula Archaeological Monument area in Hidalgo, overlooking the presence of an altar once used for human sacrifice.

During construction of the still-unfinished railroad, the team found the remains of a 1,000-year-old memorial altar thrown from the perimeter wall of the heritage site, according to a statement translated by experts from the National Institute of Anthropology and History (INAH), Mexico’s Ministry of Culture.

The three-story stone structure is approximately 3 by 3 feet and was constructed of decorative blocks of andesite stone. As reported by Victor Francisco Heredia Guillén, Coordinator of the Archaeological Rescue Project, the central level of the altar consists of modular slabs, which give it a unique shape, while the upper level is covered with layers of river cobbles and basalt rock.

But the discovery didn’t just involve the altar – archaeologists also made interesting discoveries in the area around the base of the altar. After crews dug around three of its four sides, they found human skeletal remains, including four skulls and several bones, possibly femurs. All the remains were found within the lower level of the altar, and archaeologists believe there may still be an undiscovered fourth side of the altar.

As the crew excavated the base of the altar, they first found two skulls, one toward the top and the other toward the southwest. Excavations progressed deep through a layer of soil covered with stucco made of lime and sand, and beneath that layer, archaeologists discovered two incomplete sets of human remains, including several vessels.

Heredia Guillen believes that there is little chance of finding complete skeletons, as it is possible that only specific parts of individuals were offered as sacrifices at the site. Experts plan to send the project’s findings to a state lab to determine the age and gender of the remains, as well as to identify any bone pathology and whether the individuals were decapitated, with one of the skulls still attached to the spinal column.

“In this instance – although metalworking was already practiced in the Postclassic period – we know that there was still cutting using obsidian or flint knives, which left cut marks on the bones,” said Heredia Guillen.

Along with the remains, the team found ceramic vessels – specifically a black bowl inside another vessel – obsidian fragments, small blades, spindle whorls, bone awls, and other everyday objects.

However, the altar was not a stand-alone monument. As the excavation progressed, the team uncovered walls with foundations and floor layers, meaning the altar may have been located in the palace courtyard. “We speculate that these structures served either as living quarters or as references to the elite – belonging to high-ranking groups – representing the remains of the palaces that once stood on this site,” said Heredia Guillen. “We know that on the outskirts of Tula, there were neighborhoods where the upper and middle classes lived, while the districts for the general public were located further away.”

The altar and possible palace provide a deeper understanding of the urban layout of the Toltec capital. “Every discovery like this expands our knowledge of one of the great civilizations of Mesoamerica and reinforces the central tenets of our cultural policy: the archaeological heritage of Mexico is the memory of our people,” said Mexican Culture Secretary Claudia Curiel de Icaza, “and the state takes responsibility for its research, preserving the present generation and protecting the present generation.”

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