Not unlike postwar America suburbs such as Levittown, Pennsylvania or Park Forest, Illinois, the Mississippians planned and built Cahokia – having successfully predicted that a population would flock to it. They created a city that was between six and nine square miles in area, with 120 earthen mounds inside its rough borders. The mound-building would have been backbreaking work, with the Mississippians digging up, hauling and stacking 55 million cubic feet over the course of a few decades, using no more than woven baskets to transport all that earth.
Cahokia’s largest mound (later called Monk’s Mound, after the French Trappists who tended to its terraced gardens in the 1800s) was the site of a sizeable building in which Cahokia’s political and spiritual leaders met, according to archaeologists. Surrounded by a wooden palisade almost two miles in circumference, the town centre was where residents, pilgrims and leaders worshipped and held ceremonies.
The Cahokia site covered an area of nine square miles. Illustration: Cahokia Mounds State Historic SiteLost cities #8: mystery of Cahokia – why did North America’s largest city vanish? | Cities | The Guardian