Researchers have now found hard evidence that the Amazon had a sophisticated and populous civilization, before the arrival of Columbus.
The finds lay to rest the notion that the region was pristine forest when the explorer landed in 1492…Although there was probably some untouched forest in the region, Heckenberger [the researcher] reckons that most was managed by the inhabitants and kept for cultural and symbolic, rather than economic, reasons. “It was probably very important to them just as Central Park is important to New Yorkers,” he says.
Here is the original link from Nature. Many individuals have been attached to “crankier” versions of this theory, suggesting that “prehistory” in the Americas was quite advanced, see here for a more skeptical take.