COLLINSVILLE, Illinois -- A thousand years ago along the banks of the Mississippi River, in what is currently southeast Illinois, there was a city that now mystifies both archeologists and anthropologists.

At its zenith, around A.D. 1050, the city that is now called Cahokia was among the largest metropolitan centers in the world. About 15,000 people lived in the city, with another 15,000 to 20,000 residing in its surrounding "suburbs" and outlying farmlands. It was the region's capital city, a place of art, grand religious rituals and science.

But by 1300, the city had become a ghost town, its carefully built structures abandoned and its population dispersed.

Archeologists continue to comb what is now the Cahokia Mounds State Historic Site, looking for clues that will tell them what happened here -- why the city and its culture vanished and why the people who lived here built more than a hundred earthen mounds, many of which are still scattered across the countryside.

Read more at the Wired News site