The traditional view is that before the arrival of the Spanish and Portuguese in the 15th century there were no complex societies in the Amazon basin – in contrast to the Andes further west where the Incas built their cities. Now deforestation, increased air travel and satellite imagery are telling a different story.
“It’s never-ending,” says Denise Schaan of the Federal University of Pará in Belém, Brazil, who made many of the new discoveries from planes or by examining Google Earth images. “Every week we find new structures.” Some of them are square or rectangular, while others form concentric circles or complex geometric figures such as hexagons and octagons connected by avenues or roads. The researchers describe them all as geoglyphs.
Their discovery, in an area of northern Bolivia and western Brazil, follows other recent reports of vast sprawls of interconnected villages known as “garden cities” in north central Brazil, dating from around AD 1400. But the structures unearthed at the garden city sites are not as consistently similar or geometric as the geoglyphs, Schaan says.