Mysterious Peruvian Holes Served Two Ancient Civilizations

Peru — New archaeological evidence suggests the legendary Monte Sierpe (Serpent Mountain) site in the southern Peruvian Andes served two distinct, critical functions for the ancient people who carved its thousands of precise holes.

Archaeologists, using modern drone mapping and microbotanical analysis of pollen, now propose the site was constructed during the Late Intermediate Period (AD 1000–1400) by the local Chincha Kingdom, a wealthy pre-Inca civilization.

The holes, each deep enough to hold a person, were likely the physical framework for a large-scale barter marketplace. Pollen evidence of maize and basket-making materials found inside the pits suggests.

The site’s location—in the Pisco Valley, between the highlands and the coast—made it an ideal meeting point for indigenous people to exchange goods like maize, cotton, coca, and chili peppers.

Goods may have been placed in the holes, with a certain number of holes containing one commodity (e.g., maize) equivalent to a certain number containing another (e.g., cotton), serving as a precursor to currency.

Following the Inca conquest of the Chincha Kingdom, the massive site was adapted for use by the rapidly expanding empire. The team believes the Incas converted Monte Sierpe into a monumental accounting and tribute collection system.

The thousands of precisely organized holes, segmented into distinct blocks, show an intricate pattern that researchers link to the structure of the khipu—the Inca\’s sophisticated, decimal-based, knotted-string record-keeping device .

Lead study author Dr. Jacob Bongers noted that the structure was essentially an early form of tax collection and resource management, allowing the vast empire to collect and quantify tribute from local communities before the Spanish conquest in 1532. Pollen from colonial-era citrus plants suggests the site was still in use for some time after the Inca Empire fell.

The new research provides crucial insight into the economic mechanisms of ancient Andean societies, which had no formal written language but successfully administered a massive empire.