Hello again. I recently finished reading 1491 by Charles C. Mann. This got me thinking; what would native American civilizations have developed into, if Europeans never established permanent settlements on the continent?
For example, let's say Constantinople never falls. The trade routes from Europe to Asia remain open, and explorers like Christopher Columbus never set sail to the west. Other Europeans do reach north America (There's considerable evidence that Basque fishermen reached the gulf of Saint Lawrence, it's pretty much proven that the Vikings reached North America but couldn't maintain a settlement) but they don't establish trade links with Native Americans and there is no government (or even major scholarly) interest in North America until the turn of the 18th Century.
What would North America look like? What would be the futures of the Missisipi Culture, Incan Empire, Aztec Civilization, etc?