I wouldn't call My Lai a national trauma. It was certainly terrible, but it was covered up for a long time and, while it was shocking, it didn't have much of an impact on America in the long run. Even today, we barely cover it in history classes.
I think better examples of "national traumas" in American history would be Pearl Harbor, Watergate, and 9/11. You could also make an argument for the Vietnam War as a whole, just not My Lai specifically.
Otherwise though, good quiz! Definitely an interesting idea and there are many things on here I haven't heard of so it was a good learning opportunity.
Can't speak to any of the other countries on here, but I'm American and I had never heard of My Lai. Vietnam is certainly covered in history classes here, but the particular events are kind of summed up as "it was all really ugly and bad, and then the Tet offensive happened and people got tired of it all."
The Chilean one is very complicated... Allende had been ignoring the Congress and arrogating power to himself. Pinochet launched a coup but it was a situation where democracy was already breaking down with no easy way out.
I think better examples of "national traumas" in American history would be Pearl Harbor, Watergate, and 9/11. You could also make an argument for the Vietnam War as a whole, just not My Lai specifically.
Otherwise though, good quiz! Definitely an interesting idea and there are many things on here I haven't heard of so it was a good learning opportunity.