New Atlas [newatlas.com]:
Over 10,000 years ago, ancient human settlers began the construction of around 4,700 artificial forest islands in ancient Amazonia, according to the results of a recently-published paper. Archaeologists believe that the islands were used for farming, and that they can still be seen to this day.
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The team used satellite data to map 6,643 forest islands located in present-day Llanos de Moxos, Bolivia. Of these, 82 were surveyed, samples were taken from 30, and four were excavated.Sixty-three of the islands were found to harbor dark sediments rich in organic matter including charcoal, burnt earth, animal bones and shells, which are indications of human occupation. It was concluded that they were not existing landscape features, and had instead been constructed completely artificially for the purpose of cultivating food.
Based on their findings, the researchers extrapolated that ancient settlers gradually built around 4,700 islands on which to grow food, with construction starting over 10,000 years ago. These forest islands had an average size of 0.5 hectares (1.2 acres), and were raised 0.5-3m (1.6-9.8 ft) above the savanna in order to remain above the water level during the wet season.
Researchers posit that the area represents another birthplace of agriculture, similar to Meso-America, Egypt, the Indus Valley, and others.