More evidence of dense Precolumbian habitation of the Amazon basin:
Hundreds of circles, squares, and other geometric shapes once hidden by forest hint at a previously unknown ancient society that flourished in the Amazon, a new study says.
Satellite images of the upper Amazon Basin taken since 1999 have revealed more than 200 geometric earthworks spanning a distance greater than 155 miles (250 kilometers).
On the one hand it's cool that they are able to find these with satellite imagery. On the other hand, it's sad that in the Amazon they can find these with techniques that were developed to find sites in deserts.