Researchers have unearthed remains of densely populated, complex urban towns in a remote region of the Amazon River Basin, the BBC reports. In an area of western Brazil thought to be virgin forest, researchers found extensive and advanced human activity, including roads, farming, wetland management, and what appear to be fish farms built prior to Europeans landing in the 15th century.
“They have quite remarkable planning and self-organization, more so than many classical examples of what people would call urbanism,” one researcher said. The 150-acre towns and smaller networks of villages contained roads (identically oriented to the summer solstice) connected through a central plaza, high walls, dams, and artificial ponds. The communities are thought to have been wiped out by diseases introduced by Europeans.