What circumstances allowed large societies in North and South America to fall to European invaders between 1492 and 1550?

It's probably definitely a matter of opinion. There are many things to take in consideration when deciding this, such as how many lives were lost/how many people were affected. If you are going by this, then your answer would be no, because there have been events with many more death's.

But in the end. It is still a horrible thing that happened in American History, and has changed many lives greatly.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.