Circular Geoglyphs in Brazil

About 20 of them they were discovered in the east of Acre since 1977, when an expedition dug the first ones ten, finding in them bits of white ceramic and stone axes. The geoglyphs disperse for the valleys of the rivers Acre, Iquiri and Abunã, between Rio Branco and Xapuri. All are geometric, they have between 50 meters and 350 meters of diameter and they are a lot, very old: between 800 and 2.500 years of age.