Cahokia Mounds State Historic Site preserves the remains of the most sophisticated prehistoric Indian civilization north of Mexico, circa A.D. 900-1300. Designated a UNESCO World Heritage Site in 1982, Cahokia is noted for its important role in the prehistory of North America. This book, written for a general audience, introduces the reader to this ancient metropolis, with its towering 100 foot-high Monks Mound and American Woodhenge sun calendar. This is the astounding story of an advanced Indian culture in North America that thrived and then declined before European contact.