Long before the Spanish came to South America, there were well-developed cultures in the Amazon region that permanently changed the landscape. In the upper Amazon region of what is now Ecuador, researchers have now discovered the remains of an extensive network of villages and ceremonial centers that were connected by elaborate roads. According to the researchers, the level of development of the systems discovered is comparable to urban systems of the Maya in Central America.
When the Spanish explorer Francisco de Orellana reported seeing large cities on the banks of this rainforest river after his Amazon expedition in 1541 and 1542, his contemporaries considered him a liar. It was only more than 400 years later, in the 1980s, that archaeologists discovered the first evidence that Orellana might have been telling the truth: They found the remains of extensive settlements along the river's course. Since the mid-1990s, researchers from various disciplines such as archeology and geosciences have worked together to uncover the history of the region.
Results from more than 20 years of research
A team led by Stéphen Rostain from the French National Center for Scientific Research (CNRS) in Paris is now presenting the surprising results from more than 20 years of field research. The results of the field research were supplemented with modern LIDAR mapping. In this process, the earth's surface is scanned from the air using lasers. In this way, for example, unevenness in the floor can be precisely mapped and analyzed for patterns. For the current study, the researchers evaluated LIDAR data from a 300 square kilometer area in what is now Ecuador, which is located in the upper Amazon region on the eastern foothills of the Andes.
“Our research uncovered the largest urban network of constructed and excavated structures known in Amazonia, whose origins date back to 2,500 years ago,” reports the team. An element of the buildings of that time that has been preserved to this day are rectangular earth platforms, which still rise about three meters above their surroundings and are on average about ten by twenty meters in size. Individual platforms are significantly larger – up to 40 by 40 meters – and, according to the researchers, probably come from ceremonial buildings. The team discovered a total of more than 6,000 of these earth platforms in the region, often arranged around a central square. The researchers identified at least 15 different settlement areas of varying sizes.
Thousands of years old road network
The investigations into the soil structures revealed a surprising peculiarity: “The most striking landscape feature is a complex road system extending over dozens of kilometers that connected the various urban centers and thus created a regional network,” report the researchers. “These were straight roads that intersected at almost right angles, without turning off at hills or ravines.” Apparently, the inhabitants of the region at the time dug the largest roads into the rainforest floor with enormous effort and built earth walls on the sides attached.
“It is very likely that the streets also had a pronounced symbolic and ritual function and were involved in building the cultural landscape of the time,” the team writes. There was agricultural land between the individual settlements. These were also connected to roads. In addition, the remains of an extensive irrigation and drainage system for the fields can still be seen today. “Such extensive early development in the upper Amazon is comparable to Maya urban systems discovered in Mexico and Guatemala,” the team writes.
According to dating, the earliest documented settlement in the region took place around 500 BC and lasted until around 300 to 600 AD. Further waves of settlement followed later. “Our dating suggests the succession of at least five different cultural communities,” the team said. “The first inhabitants from the Kilamope and Upano cultures were sedentary agricultural societies that densely populated the valley. They benefited from the fertile volcanic soils, which, according to farmers living in the area today, enable up to three harvests per year.”
From the researchers' perspective, the discovery of the pre-Columbian urban network in the upper Amazon provides evidence that the cultural and thus indigenous heritage of Amazonia is widely underestimated. “Like many others, we believe that it is crucial to thoroughly revise our preconceptions about the Amazonian world, reinterpreting contexts and concepts in the light of integrative and participatory science,” said the researchers.
Source: Stéphen Rostain (French National Center for Scientific Research, CNRS, Paris) et al., Science, doi: 10.1126/science.adi6317