|Map of the earthworks|
The Poverty Point earthworks (Louisiana, USA), are a very large construction dated to c. 3200 years ago. Among the various parts of the impressive complex is Bird Mound, which spans 50,000 square meters and needed almost 300,000 cubic meters of earth to be built.
This huge task was previously thought to have been accomplished in a long time, however new research of the layers indicates the opposite: that it was finished in just three months, what apparently required thousands of people passing baskets of earth in "bucket brigade" style.
"Given that a band of 25-30 people is considered quite large for most hunter-gatherer communities, it's truly amazing that this ancient society could bring together a group of nearly 10,000 people, find some way to feed them and get this mound built in a matter of months," Kidder says.
One caveat is that they surely were not "hunter-gatherers" but at least part-time farmers but it is still an impressive feat.