What is interesting is that high school teaches you when the settlers arrived in the Americas; they discovered small tribes of "barbaric" people. HOWEVER, archaeologists & anthropologists are beginning to discover or argue (as this article appropriately indicates) North and South America were already thriving populaces of huge tribes/forms of government that had advanced trade routes and other technological advances thought not to have existed initially amongst the natives. The theory exists that these native tribes had already endured tremendous decreases in population due to rampant diseases and that is why their tribes were so small when the settlers first arrived. of course, their numbers dwindled further once the settlers introduced small pox and syphillis but we already knew that... A really interesting read that covers a lot of this theory is "1491"- can't recall the author, but it's rather enlightening- cheers!