Cahokia

Excavating in East St. Louis in advance of an approaching freeway and future development, archaeologists have uncovered the remains of a sophisticated American Indian settlement nearly a thousand years old that "no one knew existed."
Jun 4, 2012   NPR
<em>Per Square Mile</em> recount the history of Cahokia, a Mississipian settlement that was the biggest city in America from about 1250 to 1800.
Feb 11, 2011   Per Square Mile