A previously unknown complex of large geometric stone structures has been discovered in the remote Cordillera del Tigre in Argentina, prompting an international archaeological investigation into its origins and purpose.
Located more than 3,000 metres above sea level in the mountains of Mendoza province, the site contains large circular structures connected by passageways, along with stone walls, ditches and excavated areas.
Some of the circles measure between 27 and 35 metres in diameter, making the scale and arrangement of the complex particularly striking when viewed from above.
Researchers have described the discovery as unprecedented for the archaeology of the region, although its age, builders and original purpose have yet to be established.
Discovery began with satellite images
The site was first identified remotely in May 2025, when Mendoza mountaineer Carlos Gobbi was examining satellite imagery and digital maps of the mountainous region.
Gobbi noticed geometric formations that appeared to differ markedly from the surrounding natural landscape.
Reaching the structures proved considerably more difficult. The isolated location is characterised by scarce water, difficult terrain and little or no communications infrastructure.
After two unsuccessful attempts because of weather and geographical conditions, Gobbi, Adrián Radich and Gabriel Orofino eventually reached the site on 14 February 2026 following a four-day journey through the mountains.
Their arrival allowed the unusual formations previously visible from satellite imagery to be examined at ground level.
Researchers found extensive stone constructions, including large circles linked by corridors. Other features include partially buried stones incorporated into ditches resembling channels, alongside walls constructed above ground.
The overall arrangement is particularly apparent from an aerial perspective, leading to comparisons with Peru’s famous Nazca Lines. Researchers have stressed, however, that the Mendoza structures represent a distinct archaeological discovery and that further investigation is required before firm conclusions can be reached.
Was it a ceremonial site?
One of the central mysteries is why such a substantial complex was constructed in such an inhospitable high-altitude environment.
Researchers have so far reported finding no pottery fragments, food remains or other surface evidence normally associated with permanent domestic occupation.
The absence of those materials has led specialists to investigate whether the complex instead served a ritual, symbolic or ceremonial purpose.
Another possibility being considered is that the structures could be associated with activity during the Inca period or with pre-Hispanic populations that occupied the region before Inca expansion. Neither hypothesis has yet been confirmed.
Researchers involved in the investigation say there are no known published records of a comparable archaeological site in Mendoza.
International project to investigate mystery
Scientific investigation of the complex is being undertaken through ArqueoAndes, a binational research project involving specialists from Argentina and Spain.
Researchers associated with the Argentine Institute of Snow Research, Glaciology and Environmental Sciences (IANIGLA-CONICET) and Spain’s University of Jaén are participating in the project, which examines human occupation and the transformation of high-mountain landscapes.
The next stage of the investigation is expected to combine archaeological fieldwork, sediment analysis and remote-sensing techniques.
Scientists hope those studies will help determine when the structures were built, how they were constructed and what activities took place there.
Until that work is completed, the vast stone circles and passageways of the Cordillera del Tigre remain an archaeological puzzle — and potentially important new evidence of how pre-Hispanic communities interacted with some of the highest and most challenging landscapes of the Andes.
Sources : Diario De Cuyo