This video explains the Cahokia Mounds in present-day Cahokia, Illinois, which once had a population of 20,000 people, being the largest city in North America at the time.

Following are points from the video:

— The Cahokia Mounds settlement is located at the confluence of three rivers that provided food and transportation, and it was once the home to as many as 20,000 people of the Mississippian culture in 1150 AD.

— It was a large city that had suburbs, permanent houses, and markets.

— People lived in thatched huts that were grouped into neighborhoods.

— Rising above the huts were mounds that were used as platforms for homes of the elite.

— The city had 120 mounts, and 80 still exist.

— The culture cultivated corn in large fields, which allowed for the rapid growth of their population and it was a resource to trade with people from other regions, where sea shells from the Gulf of Mexico and copper from the north have been discovered by archeologists.

— The society of highly socially stratified where most residents worked to support the local ruling class.

— A solar calendar “wood henge” was discovered when a highway was being constructed in the area.

— A likely chieftain was found buried inside a mound laying on 20,000 shell beads along with six attendants buried with him.  Another area contains the remains of 300 people, with half being young women who had been sacrificed, with the mound being constructed on top of them.

— It was a “planned community” where pathways connected areas.

— The height of the population of the area occurred at about 1150 AD with 20,000 people, however 150 years later the entire site was abandoned, but the reason for it being abandoned is a mystery.  People speculate that it might have been abandoned due to a shift in the climate, poor nutrition due to an over-dependency on corn, and problems with managing the waste that was generated by such a large population.