When in the 16th century the Spanish conqueror Francisco de Orellana sailed the Amazon River, he said that there were big cities on both sides of the river. Few believed then, let alone in the following centuries, when no trace of what the conquest itself had destroyed was found.

But French archaeologist Stéphen Rostain has studied the Ecuadorian Amazon in recent years using LiDAR technology and has just published the result in Science magazine: It has identified over 6,000 platforms and structures connected through a wide network of “roads” and surrounded by farmland using complex drainage systems. He has identified a total of 15 cities. The conqueror was therefore right.