entering the whirlpool

It's just a matter of making a big enough impression that a whole generation notices. And I mean, disasters are generally more sudden & easier to see. If there were an amazingly good sudden event, people would remember that too. But I mean, world peace or cures for AIDS aren't the sort of thing that happen all at once. It's like not being able to pinpoint the moment you fall in love or whatever... but you can tell the precise moment somebody dies.