So, here's an idea. What if, ages ago when we landed on this continent, we didn't find less advanced natives? What if we landed here and there was a civilization already built, greater than the countries of Europe at the time? Imagine that. What an interesting conflict that would make for the history books. Imagine one of two things happening- The New World destroys The Old World, or The New World enlightens the old, and the world prospers for a bit until war breaks out. Imagine Europe gaining such knowledge from the Natives, and using it later to destroy them. Or to destroy other Europeans. Or, imagine if European explorers continued to send expeditions to The New World, and The New World destroyed them and never let them return. The world really would seem flat then. I mean why else would every ship never return? They fell off the edge of the world of course! It's a fascinating idea if you ask me. And I'm a little surprised it didn't happen actually. Europe was stagnant for years in its advancement due to the Black Plague, the Natives had a chance to advance. But then again, I suppose it wasn't in most of their culture to do such a thing. There were few nations who weren't nomads, and they were more advanced but still... They weren't better than the Europeans.
One last thing. When the Vikings came over and raided Europe ages ago, the Catholic Church believed that they were demons sent to make the people atone for their sins. Imagine what they would think had a vastly superior nation shown up on their shores and taken over everything. The Vikings assaulted, yes, but imagine dominance of all of Europe and eventually Asia due to technology never seen before. It would be startling and would shake the foundation of all religions. And yes I realize this did happen to the Natives here, but it's an interesting twist for us to be destroyed by something we found like that. I would love to see that reality, really. Someone make a movie, I'll watch it.