The Band of Holes at Monte Sierpe in southern Peru is now likely to have been part of an Indigenous system for accounting and exchange before European contact. The feature is a 1.5-kilometer line of more than 5,200 evenly spaced pits, each roughly one to two meters across and up to a meter deep. The formation rose to prominence when National Geographic published aerial photographs in 1933, but its purpose remained debated for decades due to haze and a lack of artifacts on the ground.
An international team led by Jacob Bongers (University of Sydney) and including Charles Stanish (University of South Florida) combined microbotanical sediment analysis with drone photography to reassess the site. Microbotanical traces of maize and wild plants used for weaving and packaging were recovered from hole sediments. High-resolution drone images revealed the rows are segmented and follow a mathematical pattern that resembles khipus, the Inca knotted-string devices used for counting.
Taken together, the evidence suggests Monte Sierpe functioned as a monumental system of accounting, possibly linked to Inca tribute collection or state-administered regional trade. The site lies between two known Inca administrative centers and near pre-Hispanic roads, in a transitional ecological zone where highland and coastal groups met to trade. Researchers propose the Chincha Kingdom first used the site as a regulated marketplace, later adapted by the Inca Empire for storage and redistribution. The team plans further study of the plant remains to learn their types, origins and any medicinal properties.
- Methods: microbotanical sediment analysis and drone imagery.
- Findings: maize and wild plant traces plus patterned rows.
- Interpretation: monumental accounting linked to trade or tribute.
Difficult words
- accounting — system for recording and tracking numbers or goods
- microbotanical — very small plant remains studied in samples
- sediment — material like soil or particles that settlesediments
- khipu — knotted-string device used for recording numberskhipus
- tribute — payment or goods given to a ruler or state
- redistribution — the process of giving goods again to others
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Discussion questions
- How does the site's position between highland and coastal centers support the idea it was linked to trade or marketplaces?
- What kinds of additional evidence would make the interpretation of accounting or tribute more convincing?
- How could further study of the plant remains help us understand the origins or uses of the goods found at the site?
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