The Amazon is known today as a rainforest whose natural resources are under threat from human incursion.
But before Europeans arrived in the 15th century it was home to dense populations served by a complex of public plazas, roads and canals.
Researchers from the University of Florida at Gainesville challenge the traditional view that it was a "pristine" habitat containing only small numbers of scattered villages. Michael Heckenberger, an assistant professor at the university's department of anthropology, says the jungle was being tamed and altered by humans well before Christopher Columbus arrived in the New World in 1492.
He reports his 10-year study, mapping and excavating a 1,000-square kilometre area around the Upper Xingu, a tributary of the Amazon in Brazil, in the journal Science today.
Clark Erickson, from the University of Pennsylvania in Philadelphia, says in an accompanying news article: "These people were doing something we don't seem very successful at: sustaining populations without destroying biodiversity."
Professor Heckenberger sayshuman population declined in the Amazon because of diseases introduced by Westerners such as smallpox and influenza. His studies were assisted by two indigenous chiefs from the region. They turned up man-made features that date back more than 500 years, including overgrown canals and roads up to 50 metres wide. There was evidence of large central plazas, canals and bridges and defensive moats around villages.
The researchers say: "Evidence ... suggests a highly elaborate built environment, rivalling many contemporary societies of the Americas."Reuse content