I think 9/11 is a generational thing. If you were late teens to early thirties when it happened it really hit you badly. Not just the event itself but its implications. Was this the beginning of WW3? Apart from Pearl Harbor, which did push the United States into WW2, the US had never been so attacked on its own soil before.
It was a scary time and we thought the world might change forever. In some ways it did. The Cold War had just been declared over and now this Islamic Terrorism threat was going to take its place, apparently. There had been rumblings of it with the Gulf War but not really.
Perhaps incidentally, 9/11 was kind of the start of the digital age. It was the first world event covered by rolling 24 hour news, the first time you got told something really important via your mobile phone.
Possibly, the great generational event that late teens to thirty year olds today will talk about is Covid. Of course, it affected everybody's lives but your late teens and twenties are your planning for the future years. The should be happy time when everything is possible. Things to do, people to meet.
It's almost as if for some reason, whoever runs the world likes to put a spanner in the works every twenty five years or so just so everything doesn't get too out of hand with peace, prosperity and goodwill to all men.
I'm not sure what the generational blight of the 60's/70's was. I wasn't around. Vietnam? The Day JFK Was Shot?
Certainly before that was WW2, then before that, WW1. I wasn't around for them either but they were far enough in the past to be taught about in school and talked about by parents and grandparents.
Just musings really and of course there's people who breeze through life and don't really reflect too deeply on world events, have private problems that take occupy them much more immediately or live in countries or are in social groups where or in which their lives are punctuated by different politics and concerns.
Also, history isn't really in such neat chunks of 25 years starting from a clear Year Zero so I'll stop now.