A once-thought virgin forest in a remote area of the Amazon had been in fact a densely populated place. Researchers recently discovered traces of widespread human activity which contradicts the anthropologists’ theory that the only cradle of "urbanism" in pre-Columbian South America was in the Andes Mountains.

Archeologists found traces of a numerous settlements that were connected by road networks and had been built around plazas. There was also evidence of the main activities of the dwellers of that urban community such as farming, wetland management, and fishing.

According to the research report, the settlement dates back to the period prior to when the Europeans discovered that part of the continent. The "medieval" urban community was located in the Upper Xingu region of the Brazilian Amazon.

"These are not cities, but this is urbanism, built around towns," said Professor Mike Heckenberger, from the University of Florida.

Heckenberger said he was amazed by the "remarkable planning and self-organization." The villages were built in clusters following geometric patterns comparable to the European villages in that same era.

The urban community was surrounded by large walls composed of earthworks. Each road was pointing north-east to south-west in order to keep with the mid-year summer solstice. Researchers also found a series of dams and artificial ponds which the dwellers used for fish farming. Researchers believe the urban community of Upper Xingu was composed of tens of thousands of people.

The main reason why urbanism was a very rare thing in the Amazon during that period was the fact that local people did not have the ability to centralize production of resources and did not believe they really needed to centralize into cities.

The inhabitants of those settlements are thought have been wiped out when the European colonists arrived there.