Mysterious giant stone circles turn up high in Argentina’s Andes

A previously unknown complex of large stone circles has turned up more than 3,000 meters up in Argentina’s Cordillera del Tigre, in Mendoza province, after a mountaineer scanning satellite imagery noticed geometric shapes that did not belong on a bare, glacier-carved ridge. Carlos Gobbi first spotted the pattern in May 2025, and it took until February 14, 2026 for a small ground team to physically reach the site and confirm that dry-stacked stone walls, not a trick of light on rock, had produced the shapes.

What the team found were not simple rings. Individual circles measure between 27 and 35 meters across, roughly the footprint of a city block, and several are linked by stone passageways and corridors rather than standing as isolated features, alongside ditches that resemble channels and patches of ground that appear to have been deliberately excavated.

Part of the reason the site stayed undocumented for so long is straightforward geography. The Cordillera del Tigre sits far from any paved road or established trekking route, at an elevation where snow and thin air limit the field season to a narrow stretch of the year, and satellite coverage of that stretch of the Andes had simply never been examined closely enough by anyone looking for archaeology rather than glaciers or mineral deposits.

A Satellite Image Spotted What No Ground Survey Had

Gobbi, an experienced Mendoza mountaineer, was reviewing digital cartographic tools in May 2025 when he noticed the geometric outlines during a routine look at terrain far from any marked trail. Reaching the site on foot took a multi-day trek across remote high-altitude ground, and the party that finally arrived on February 14, 2026, Gobbi accompanied by fellow climbers Adrián Radich and Gabriel Orofino, found the circles exactly where the satellite images had placed them.

No prior survey, official map, or published archaeological record had ever noted the site. Researchers with the ArqueoAndes project put it plainly once they had examined the corridors and channels for themselves: “There are no precedents in notes or in publications. It is an unprecedented discovery for archaeology,” a statement, translated from Spanish, that captures how far outside the existing record the find sits.

Circles Wide Enough to Enclose a City Block

The 27-to-35-meter circles are built from stacked dry stone rather than mortared construction, connected in places by walls and corridors that turn individual rings into a linked complex rather than a scattered set of separate monuments. Ditches resembling channels cut between some of the structures, and patches of ground nearby show signs of deliberate excavation, though researchers have not yet determined what, if anything, was removed from them.

Surface surveys have turned up no pottery fragments and no food remains anywhere on the site, an absence that rules out the most obvious explanation: that people simply lived there.

Why Archaeologists Aren’t Calling Them Geoglyphs Yet

That missing domestic debris is why researchers with ArqueoAndes, the binational project led by Cristina Prieto-Olavarría and Horacio Chiavazza, currently favor a ritual, symbolic, or ceremonial purpose over an ordinary settlement, with a possible connection to Inca-period activity in the region or to pre-Hispanic populations who occupied the area before the Inca empire expanded into it.

Some coverage has likened the site to Peru’s Nazca Lines, the famous desert geoglyphs visible from the air, but researchers involved in the Cordillera del Tigre project describe their find as a distinct archaeological discovery rather than a regional cousin of Nazca, since the circles are built up from stacked stone at high altitude rather than etched into a desert surface near sea level. Even the label “geoglyph” is provisional here, applied loosely by some outlets to structures that raise stone rather than remove it, a distinction the research team has not endorsed outright.

A Binational Team Betting on Drones and Sediment

No age has been established for the circles, and researchers say the estimate could eventually land anywhere from a pre-Inca period through the era of Inca expansion into the region, since no organic material recovered so far has proven suitable for dating. That uncertainty is now the project’s central problem to solve, not a footnote to an otherwise settled find.

IANIGLA-CONICET, the Argentine glaciology and environmental-science institute already tied to the discovery through Prieto-Olavarría and Chiavazza, is working the site jointly with Spain’s University of Jaén under the ArqueoAndes program, which plans to combine architectural surveys, sediment sampling, and remote-sensing work to pin down when the circles were built and how they were used. Until that work runs its course, the walls above 3,000 meters remain exactly what the researchers called them in the days after they first stood inside one: a find with no precedent in the record.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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