Cahokia is the site of an ancient Native American city (650-1400 AD) near Collinsville, Illinois in the American Bottom floodplain, across the Mississippi River from St. Louis, Missouri. The 2,200-acre (8.9 km²) site includes numerous man-made earthen mounds. Cahokia Mounds is the largest archaeological site related to the Mississippian culture. [1]. It is a designated site for state protection, a National Historic Landmark, and a World Heritage Site. The term "Cahokian" is sometimes used as a term for the Mississippian culture. The Mississippians developed highly advanced societies in eastern North America centuries before the arrival of Europeans. http://en.wikipedia.org/wiki/Cahokia

The Cahokia Mounds I know of are a set of mounds located near St. Louis Missouri. From what I remember, these mounds are the remnants of what was the largest city in North America until Philadelphia. It is home to Monks Mound (so called because a group of monks made their home on it once), which is the largest earthen construction in North America (at least). Okay, what else... sorry, my brain is slow tonight. Oh, yeah. Corn. It all started with corn. Corn and beans from Central America, that is; a migration of people and knowledge from Central America brought a lot of agriculture up north to what we call the Woodland People. We know this because A, they had the technology and B, artistic and religious concepts straight from Mexico were found in Cahokia. This abundance of agricultural know-how led, as always, to the development of large cities (in Cahokia's case, the largest!). So the Woodland People became the Moundbuilders. The Moundbuilders were cheifdoms, unlike the tribal Woodland People (cheifdoms seem to always pop up when there is an abundance of wealth and no one to take it, don't they?), and the mounds they built were often burial mounds for their higher-ups and riches. Cahokia is special because of a few features. Its size is, of course, extraordinary (actually, St. Louis was built over quite a few mounds, and in its early days was called Mound City). It also appears to be built in a certain pattern, with mounds and woodhenges (yes, there were more than one) popping up at exact geometrical locations. One of these mounds, excavated fairly recently by a man who saw a pattern in Cahokia and just started digging where he thought something ought to be, contained a man on a hawk-shaped bed of ornamental arrowheads and shell beads (an expensive burial shroud at the time); nearby was a pit full of young women (forgive me, I forget the number) and another grave with either 10 or 12 other brutally murdered men and women. So the shape of the site is important. The site itself tells an excellent story of the rise and fall of civilization; Cahokia grew to be a seething metropolis (complete with suburbs); internal dissent struck (they actually built barricades within the city); they depleted their natural resources and screwed up their diets by eating only corn; lost faith in the chief; and the whole place was abandoned mysteriously just like the Mayan cities. In a way, it's very mysterious because we don't know for sure what happened, but in another it's extremely informative because they left behind so many artifacts. And of course you have Monks Mound, the whopper. It's a huge one, obviously, but it's also flat-topped because on top of the mound was where the chief lived. The chief was a God, so the idea was that he lived halfway between Heaven and Earth. All of the mounds were works of architectural art; the builders knew what they were doing. The fact is that the mounds are really just piles of dirt. But they've been standing for over a thousand years, so a lot of work and artistry and experience went into them. I can get you years and stats and numbers and such once I dig out my anthropology notes, but hopefully what I've given you helps.