Some estimates put the first human settlements in the Amazon at 32,000 to 39,000 years ago. Since that time, Amazon people have developed lifestyles that are well integrated with the benefits and constraints of rainforests.
An estimated 7-10 million Amerindians (the term for American Indigenous peoples) lived in American rainforests, half of them in Brazil, at the time of European arrival. When Pizarro arrived in Peru, more land was under cultivation and more food was being produced in the Andean region than today.
He claimed that they were one large supercontinent called Pangaea. His evidence for his claim was that the general shapes of the separate continents and how they can fit together if you arrange them. He noticed patterns in the mountain ranges; when all the continents are together the ranges line up with one another.
Mountain Peaks and Plautaeu