Location
Cahokia Mounds is located in southern Illinois, just across the river from St. Louis, Missouri.
History
Humans arrived at Cahokia around 700 AD, but around 1050 the population erupted for unknown reasons. At its peak, the city was home to 10-15,000 people, with the population estimated to have been as large as 40,000. That means it may have been the biggest city of it's time. The center of Cahokia, both geographically and spiritually, was the Monk's Mound. It was the home of the city's Great Sun, who lived in a wooden temple at the top. He ruled over a structure similar to that of the Maya or ancient Egyptians, with classes of slaves and commoners. For some reason, by 1300, the magnificent city had been abandoned and it's people disappeared. It's possible that the construction of the great mound lead to Cahokia's destruction by overexploiting natural resources. Agricultural degradation, droughts, and overpopulation may also have been factors.
Monks Mound
Monks Mound is the largest prehistoric earthen structure in North America spanning an area of nearly 14 acres. There was a large building on top of Monks Mound, possibly a temple or the home of the chief. It may have measured about 5,000 square feet and 50 feet high. In addition to being the largest mound in North America, it is the largest pre-columbian earthen structure in all of the Americas. Monks Mound is a testament to the sophisticated engineering skills of the Mississppians. This land was thought to be a formation, but further investigation showed that it was leveled and filled. It is the largest of four similar plazas in other areas of the Cahokia Mounds. Many structures and mounds were surrounded by remains of watchtowers and defensive structures, suggesting the area was used defensively.
Stockade
Excavations that begun in 1966 eventually confirmed that an enormous, two-mile-long stockade surrounded the central portion of Cahokia. The wall appears to have been constructed in 1100 A.D. and then rebuilt three times over a period of 200 years. Each construction required 15,000-20,000 oak and hickory logs, one foot in diameter and twenty feet tall. The logs were sunk into a trench four to five feet deep and were likely supported with poles or wrapped with saplings. The stockade walls have been covered with clay to protect them from fire and moisture. There's no evidence of invasion, so people question about the making of the Stockade. It most likely served as a social barrier, however, three things lead most archaeologists to believe that it was a defensive structure. The great height of the wall, ledges from which archers could shoot arrows, and evidence that portions of the wall were hastily built.