This Millennium-Old Sacrificial Altar in Mexico Belonged to a Civilization That Thrived Before the Aztecs

Surrounded by human skulls, the artifact was uncovered at the site of the Toltec people’s capital in central Mexico ahead of construction of a new railway project

Sonja Anderson | Daily Correspondent

April 14, 2026

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As part of a railroad construction project in Mexico, researchers recently unearthed a tiered stone structure about three feet wide, surrounded by human skulls and femurs. Archaeologists say it’s a sacrificial altar built by the Toltec people some 1,000 years ago.

The Toltecs, a Nahuatl-speaking tribe, dominated central Mexico between about the 10th and 12th centuries C.E., before being toppled by the Aztecs. Experts excavated the altar just outside of the Tula Archaeological Monument Zone, which encompasses the ruins of the Toltec capital.

According to a translated statement from Mexico’s National Institute of Anthropology and History (INAH), the altar dates to between 900 and 1150 C.E. The square-shaped monument is composed of three tiers of stone. In addition to human bones, archaeologists found ceramic bowls, obsidian fragments and blades at the site.

“Altars were a common component of Toltec civic, ceremonial and residential architecture,” Dan M. Healan, an emeritus archaeologist at Tulane University, tells the Art Newspaper’s Constanza Ontiveros Valdés.

The city of Tula, located in the Mexican state of Hidalgo, was built around the mid-ninth century C.E. Archaeological remains include a major civic center composed of a temple pyramid and plaza, as well as a palace complex, two ball courts and two other temple pyramids. According to a 1972 archaeological survey, the city spanned more than six square miles and housed as many as 60,000 people.

Like many Mesoamerican Indigenous civilizations, the Toltecs were polytheistic, and one of Tula’s pyramids was likely dedicated to Quetzalcóatl, the “Feathered Serpent” god. The Toltecs also worshipped gods through human sacrifices.

Víctor Francisco Heredia Guillén, the coordinator of INAH’s salvage project, says in the statement that he doubts the researchers will find complete skeletons at the new site. Perhaps, he adds, only fragments of sacrificed individuals were left at the altar. The bones will soon be analyzed at a physical anthropology laboratory, where researchers will attempt to determine the age, sex and bone pathologies of the people whose remains were found, and whether they were decapitated. Per the statement, one of the skulls is still attached to a spinal cord.

By this time, during the Postclassic period, the Toltecs were practicing metalwork. But Heredia Guillén says in the statement that they decapitated people with knives made of obsidian or flint, which left cut marks on the bones.

Near the altar, researchers found the foundations of walls and remnants of a floor. These indicate that the monument may have been surrounded by a palace courtyard. The researchers hypothesize that the walls and floor were part of elite living quarters, Heredia Guillén says in the statement. They’re aware that Tula’s immediate outskirts were inhabited by upper and middle classes, while common people dwelled further afield.

The altar dates to the Toltec civilization’s most powerful period, which began after they sacked and burned Teotihuacán—an older, larger city known today for its twin Pyramids of the Sun and Moon. The Toltecs formed a small empire and became known for violent militarism. They were also fine craftspeople, producing metalwork, ceramics, carved columns and giant statues. But in the 12th century, several other Indigenous peoples, like the Chichimec and the Aztec, invaded Tula and put an end to Toltec dominance.

Recent train projects in Mexico have raised concerns about disruption to fragile ecosystems and archaeological sites. “They are literally unearthing things like ancient Mayan temples and human remains as that construction continues,” said NBC News’ Gadi Schwartz in 2022. But Mexican political leaders have made it a priority to continue to build quickly.

Researchers from INAH have been exploring the route ahead of construction of a rail line of more than 140 miles between Mexico City and Querétaro. “In preliminary fieldwork, we have identified 12 areas of archaeological interest, including objects and monuments of varying scales,” Heredia Guillén tells the Art Newspaper. “The fully preserved altar formed part of larger constructions, of which only foundations remain, supporting hypotheses about administrative areas beyond the archaeological zone.”

Emmanuel Hernández Zapata, chief field archaeologist, says in the statement that the research team created drawings and took drone photographs of the altar site. The ceramic bowls found nearby will be sent to a laboratory for conservation and analysis, and experts are currently evaluating conservation options for the altar itself.

Sonja Anderson | Read More

Sonja Anderson is a writer and reporter based in Chicago.