Almost five thousand years old stone plaza discovered in the Andes

The megalithic structure is one of the oldest ever found.

A team of anthropologists has discovered a 4,750-year-old megalithic circular plaza in the Cajamarca River basin in Peru. It is one of the earliest known monumental and megalithic structures in the northern Peruvian Andes and one of the earliest examples in the Western Hemisphere.

This circular plaza, discovered at the archaeological site of Kallakpuma, represents one of the earliest examples of monumental construction in the Andean region. The structure, consisting of two concentric walls built from vertically arranged megalithic stones, shows no signs of domestic habitation, suggesting that its main function was ceremonial. The results were published in the journal Science Advances.

Monumental architecture is central to many aspects of human social organization, but the driving forces behind its origins remain poorly understood. This form of architecture is deliberately designed to be larger and sometimes more complex than necessary given its intended function.

Early, well-known examples of ceremonial architecture of this kind include Göbekli Tepe in Turkey, Stonehenge in England, and the Great Pyramids of Giza in Egypt, which were built by 9000 BC, 2900 BC, and 2650 BC respectively.

Göbekli Tepe is particularly important here as it was built during the Pre-Pottery Neolithic by hunting, gathering and foraging peoples on the cusp of sedentism and food production.

The newly discovered megalithic plaza was built during the Late Pre-Pottery period, as early as 2850 BC. This construction method has never been used in the Andes before and is different from other monumental circular plazas in the region.

“This structure was built approximately 100 years before the Great Pyramids of Egypt and around the same time as Stonehenge,” noted anthropologist Jason Toohey. He speculated that it was a gathering place and ceremonial site for some of the earliest people to live in this part of the Cajamarca Valley.

Kallakpuma Square is formed by two concentric walls and is about 18 m in diameter. The people living in this area led a predominantly hunting and gathering lifestyle and only shortly before the construction of the structure began to grow crops and domesticate animals.

“The Late Pre-Pottery Period, during which Kallakpuma Plaza was built, was a time of socio-economic transition in the Andes,” the researchers write. “On the central coast, the communities that came together to create massive mounds at places like Caral were not yet full-fledged farmers, but were involved in complex systems of exchange with coastal fishing communities.”

In the northern highlands of Peru, the people who built the plaza at Callakpuma began experimenting with food production, but they were also likely still relatively mobile hunter-gatherers.

According to scholars, as with early monumental collective architecture outside South America, such as at Gobekli Tepe, the construction of monumental ritual architecture in the Late Pre-Pottery period of the coastal and highland areas of the central Andes represented a changing social world, perhaps involving a shift in belief systems associated with small groups, to more collective and regionally oriented faith and action.