Monumental Burial Mounds Rewrite Ancient History

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Ancient works of impressive architecture inspire awe the world over. The Great Pyramid of Giza. The Parthenon in Athens. Machu Picchu in Peru. But archaeologists had previously assumed that it took a complex society, with institutionalized inequality, to give birth to such massive works.

Now, researchers working at a site called Kaillachuro in the Titicaca Basin of the Peruvian Andes have determined that monumental burial mounds were built by egalitarian hunter-gatherer groups over the course of centuries. The Andean architects started constructing the mounds about 5,300 years ago and continued to build upon existing burial sites for more than 2,000 years, which challenges the conventional wisdom that structures of this scale only arose from civilizations with social hierarchy and controlled labor forces.

Scientists used radiocarbon dating to analyze remains in the series of nine low-lying mounds, which were unearthed by an archaeologist in 1995, and published their findings in a recent issue of the journal Antiquity.

“Most researchers in the Andes argue that monumental architecture is a product of elites, intentionally constructed as a space of centralized power,” said the study’s corresponding author Luis Flores-Blanco, a postdoctoral researcher at Arizona State University, in a statement. “We propose that monumentality can emerge from hunter-gatherer groups without institutionalized inequality.”

The mounds also push the timeline for such works in the Andean highlands back significantly—archaeologists previously thought that such works didn’t appear in that region until 1,500 years later. Starting with rudimentary burial pits in the ground, the mounds took shape over the centuries as their builders constructed increasingly elaborate memorials to their deceased ancestors.

“Kaillachuro is an extraordinary find because it shows that mounds were used in ritual contexts for over 2,000 years—though not necessarily continuously,” Flores-Blanco added.

The authors of the paper suggest that such building practices—centered on memorial rituals—created visible reminders of the dead and may have given rise to socioeconomic transformations that paved the way for more complex societies.

Lead images courtesy of Cambridge University Press

• Bob Grant

  Posted on July 4, 2025

  Bob Grant is the deputy editor at Nautilus.