What are the large geometric earthworks found in Brazil’s Amazon region called?

The large geometric earthworks found in Brazil’s Amazon region are called Amazonian geoglyphs.

These structures are usually ditches and raised banks arranged in circles, squares, rectangles, and other precise geometric forms. Many are located in the Brazilian state of Acre, where satellite imagery and deforestation revealed features hidden beneath dense forest.

Archaeologists generally associate the earthworks with pre-Columbian societies. Their exact purposes varied or remain uncertain, but proposed uses include gathering places, ceremonial spaces, defensive sites, and areas connected with settlement. Their existence challenges the older idea that the ancient Amazon was occupied only by small, highly mobile groups.

Amazonian geoglyphs are not the same as Peru’s famous Nazca Lines. Nazca figures were made mainly by removing dark surface stones, whereas many Amazonian examples were constructed as large enclosed earthwork designs. Research continues because the rainforest preserves many sites beneath vegetation.