Enigmatic Earthworks in the middle of the Amazon jungle
Deep in the Amazon rain forest a mystery: geometric earthworks, stretching out in circles and squares that can be as big as a city block, appear to have been built up to 2,000 years ago.Were the broken ceramics found near the entrances used for ritual sacrifices? Why were they here? The answer remains a mystery. More than 450 of these geoglyphs are concentrated within Acre State in Brazil.