Ortelius World Map of 1570 depicted no fewer than 21 major coastal cities in North America (above the Rio Grande) and he had no knowledge of the cities along the major inland rivers or on the shores of the Great Lakes. Cahokia, located on Mississippi River in (now) southwestern Illinois. Most C14 tests indicate 200 AD to 1000 AD. Featured double palisade, copper industry, sustained population > 20,000, at times may have exceeded 50,000, more than lived in London (or Teotihuacan, for that matter) at the time, largest earthwork in North America (Monk's Mound has volume greater than Great Pyramid at Giza), artifacts from raw materials that came from Yellowstone, South Carolina, and from Gulf coast. Materials, some at least, that make up Monk's mound came from sources hundreds of miles away (bibliotecapleyades.net/arqueologia/monks_mound.htm). No, they couldn't possibly have been capable of civilization or long distance trade. Poverty Point, Louisiana, along the Mississippee River, some C14 dates to 7,500 bce. Seven concentric earthen dikes originally, some now cut by river course changes, estimated 4 million anthropomorphic artifacts, estimated max population 50,000. Trade goods included raw copper from Upper Michigan, Indiana blue flint, Yellowstone obsidian, mica from both Illinois and South Carolina, lead from Iowa, and grizzly bear claws from parts unknown. No, they weren't capable of long distance trade, surely. Fort Ancient Culture (usually described as "Hopewell"), Ohio. Geometric forms (circles, squares, etc with perfect astronomical alignments) in earthworks, a wide road that stretches 130 miles and straight as a die, conch shells, more Yellowstone obsidian, more Upper Michigan copper, more mica from both sources (including what was a single sheet over five feet across at time of burial), indications of iron furnaces being operated. No they couldn't have traded either. Or performed geometry. Shawnee Fort, Ohio. Vast water works (dams, irrigation ditches, locks, canals, possibly even aqueducts). More discoveries each dig season. Chaco Canyon, The people built monumental public and ceremonial buildings in the canyon. The buildings were massive, multi-storied masonry structures of rooms, kivas, terraces, and plazas. The largest building-Pueblo Bonito-is estimated to have contained over 600 rooms and rose four, possibly five, stories high. Hundreds of miles of formal roads radiated out from the canyon and linked Chaco to distant communities. Surely they were neither civilized nor capable of long distance trade (and they drank cocoa).