Archeologists uncovered nearly 400 previously unknown ancient earthworks beneath the southwestern Amazon rainforest, revealing what is believed to be evidence of complex societies that flourished long before Spanish and Portuguese colonists arrived. The findings, published this week in the journal Nature, identified circles, squares, and other geometric formations that archeologists call geoglyphs dating from 600 B.C. to 850 A.D. using lidar, a laser-scanning technology capable of seeing under dense forest canopy. Lead author Martti Pärssinen told The New York Times that the earthworks likely hosted “festivities, political occasions, ceremonies, dance, music and also competition like ball games.” Martti PärssinenThe New York Times