Claire Bates - 2010 01 12
Hundreds of geometric monuments unearthed deep in the Amazon may have been left behind by a previously unknown society, say scientists.
Archaeologists have found more than 200 earthworks shaped as perfect circles and squares, many connected by straight roads. They have dated one site to 1283AD but say others could be from as early as 200AD.
The earthen foundations were found in a region more than 150miles across, covering northern Bolivia and Brazil’s Amazonas state.
The first ones were uncovered in 1999, after large areas of pristine forest was cleared for cattle grazing.
Sculpted from the clay rich soils of Amazonia, the earthworks are made up of 30ft wide and 10ft deep ditches alongside 3ft high walls. The largest ring ditches founds so far are 1,000ft in diameter.