Lidar reveals networks of pre-Columbian cities and towns in Bolivia

The survey also revealed previously unseen details of defensive walls and complex ceremonial buildings at 17 other settlements in the area, built by a culture about which archaeologists still know very little: the Casarabe.In the last few years, lidar—which uses infrared beams to see what lies beneath dense foliage—has helped archaeologists map a long-hidden, long-forgotten landscape of towns, fortresses, causeways, canals, terraced fields, and ceremonial sites left behind by the Maya and Olmec civilizations across a huge swath of modern Belize, Guatemala, and Mexico. The survey also revealed a thriving urban culture in an area where historians once assumed very few people lived before Spanish colonization.Previous surveys in the Llanos de Mojos, a region of northern Bolivia, had spotted the ruins of several hundred pre-Columbian monuments scattered across about 4,500 square kilometers of the plains—an area centered on the modern Bolivian town of Casarabe.