Boo hoo! Human economic development is ravaging the precious Amazon rain forest. Except, wait a moment, clearing rain forest vegetation is making it clear that people had cleared the same land centuries ago, cities, systems of irrigation, an entire unknown civilization once existed covering huge areas that have since been buried by the jungle.

In the academic journal Antiquity: Pre-Columbian geometric earthworks in the upper Purús: a complex society in western Amazonia.

The combination of land cleared of its rainforest for grazing and satellite survey have revealed a sophisticated pre-Columbian monument-building society in the upper Amazon Basin on the east side of the Andes. This hitherto unknown people constructed earthworks of precise geometric plan connected by straight orthogonal roads. Introducing us to this new civilisation, the authors show that the ‘geoglyph culture’ stretches over a region more than 250km across, and exploits both the floodplains and the uplands. They also suggest that we have so far seen no more than a tenth of it.