The advanced engineering of the ancient Americans

Some of the architectural/engineering projects in North and South America ["Indian" engineering] we cannot duplicate today.

Such as tens of thousands of mounds and pyramids constructed in North America.

One site of many:

Cahokia
[link to www.mnsu.edu]
The city of Cahokia was inhabited from 1300 to 600 BP. At its peak from 900 to 800 BP, the city covered nearly six square miles and had a population of up to 20,000. Houses were arranged in rows and around open plazas. The main agricultural fields lay outside the city. Cahokia was a planned city with elaborate public buildings and perhaps elite residences at its core. The construction of these features required an organized cooperative labor force as well as organized leadership. Astronomical, mathematical and engineering knowledge also appear to be necessary skills in the planning and construction
of the site.
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Want more? The Great achievements of the Anasazi, the megalithic engineering of the Inca and the Maya down south?
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Chew on this, MASSIVE TERRAFORMING IN BOLIVIA:

The discovery of over 500 square kilometers of artificial earthworks
[link to cyberspaceorbit.com]