Actually, there were several large cities. Tenochtitlan was one such city, and then of course there were all of the various Inca strongholds. There were also large cities on the Southern Mississippi, such as Cahokia. There may well have been many more large cities that the Europeans never learned about because they might have been destroyed by disease. Tenochtitlan alone is said to have contained 200,000 people, possibly more.And it still doesnt explain the "American" cultures, there were no great cities there (there were probably about 300,000 in mixed tribes), but yet they never advanced, past the stone age. I do believe the bow was a superior weapon to early firearms, it could fire faster and farther, but the arrowheads were still stone.
Their primary melee weapon was the tomahawk with a stone head, if they had just advanced to the bronze age, things would have been different.
Also, the Incas and possibly the Aztecs had started making weapons of copper shortly before the Europeans arrived.
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