BONN, GERMANY—A pre-Columbian landscape inhabited by the people of the Casarabe culture between A.D. 500 and 1400 has been mapped in Bolivia’s Amazon rain forest by archaeologist Heiko Prümers of the German Archaeological Institute and his colleagues, according to a Science News report. Prümers said that the lidar survey of more than 1,700 square miles revealed traces of an urban system of 26 interconnected sites, including campsites, villages, towns, monumental centers, canals, reservoirs, and straight, raised causeways under the layers of dense trees and ground cover. This type of city plan allowed for plenty of room for farming, he explained. The two largest sites in the system, Cotoca and Landívar, were protected by curved moats and defensive walls. They also had rectangular and U-shaped platform mounds, and artificial terraces supporting cone-shaped pyramids made of earth. Causeways radiated out from both sites as well, Prümers explained, which connected them to smaller sites with fewer platform mounds, and other areas that may have been reserved for specific activities, such as butchering prey. Read the original scholarly article about this research in Nature. To read about sites in northern Bolivia where hunter-gatherers settled seasonally as far back as 10,600 years ago, go to "Home on the Plains."