Traditional western views of the Amazon says that large civilizations could not exist there and since the people in this region had perishable building items instead of stone it is hard to find evidence of these civilizations. In recent decades there is evidence that there were large numbers of people who lived in this area. Large mounds, canals, causeways and ringed ditches around moated cities have been found. Pottery in Brazil has been found and dated to 6000 BCE which is older than any pottery found in the Americas, The dates of pottery in South America seems to indicate a movement from Brazil to Guiana to the west coast of South America. Hunter gatherer evidence has been found as far back as 9200 BCE. The fact that these sites do not seem to correspond to the Clovis civilizations in North America is making it difficult to explain how the Americas were actually populated since the original theories of movement across the Bering strait down through North, Central and then South America aren’t necessarily supported by the evidence found so far.

(The Great Courses – Lost Worlds of South America)