Ongoing discoveries of widespread civilization practicing agriculture and land management on the border of Bolivia and Brazil. The operative word in this article is geoglyph, but i have my doubts whether as many of these designs are going to be as purely ceremonial as the ones used down in Peru by the Nazca culture (for example.) Previous articles speculate that they are fisheries, irrigation, and the like. On the other hand, there was that report from a few years ago about a Brazilian Stonehenge. Eh, maybe geoglyphs is right.
Regardless, the trope about the traditional view about that area being lightly populated before European conquest should be retired, like the Clovis theory that introduces most articles about any evidence of human habitation of the Americas prior to 13,000 years ago.