Scientists have revealed a group of lost cities that were hidden under earthen mounds in Ecuador. Over two decades ago, these mounds and buried roads were observed by archaeologist Stéphen Rostain. Now, laser technology has been used to uncover these lost cities of the Amazon in the foothills of the Andes. These settlements are now thought to have been home to 10,000 or more farmers about 2,000 years ago, possibly for a period as long as 1,000 years. The findings have been reported in Science.
"It was a lost valley of cities," said Rostain, of the French National Center for Scientific Research (CNRS). "It's incredible."
People now known as the Upano occupied these settlements, between roughly 500 BCE to around 300 to 600 CE. This is around the same time period that the Roman Empire existed in Europe.
In what is now the Ecuadorian Amazon, people built residential and ceremonial buildings, which were surrounded by a network of agricultural fields and canals. Roads were as big as ten meters (33 feet) wide and twenty kilometers (12 miles) long.
It's challenging for modern scientists to estimate the population sizes that may have existed there, but 10,000 people or more may have resided in the area. Study co-author and archaeologist Antoine Dorison suggested that 30,000 people may have lived there at its peak.
LIDAR imaging was performed at the site. Light Detection and Ranging (LIDAR) is a sophisticated technology that can be used to generate very high resolution maps of create areas of ground elevation. LIDAR uses Global Positioning System (GPS) and a laser scanner that are mounted to an aircraft along with an Internal Navigation System. The scanner shoots pulses of the laser at the area of interest, and the pulses are reflected back. The time this process requires is used to measure distances. In this study, LIDAR imaging revealed a main thoroughfare that crosses through an urban area. Rectangular platforms can be seen along the way, which are set up in low squares in the Upano Valley in Ecuador.
Although the Amazon might be considered a wilderness that has been relatively untouched by humans, recent archeological finds have suggested that people have lived in the area in more complex ways than we appreciate. There are similar sites in Bolivia and Brazil that researchers are just beginning to study.
"There's always been an incredible diversity of people and settlements in the Amazon, not only one way to live," said Rostain. "We're just learning more about them."
Sources: The Associated Press, Science