If the OP is in his/her mid 20's, then "during their entire lifetime".
Not to be all "kids these days" about it, but millions of people read about the fall of the Berlin Wall and the Soviet Empire in their World History class, instead of living through it.
Just last week on HN I saw a comment to the effect of "I trust China over the US when it comes to political protest". That's the kind of thing people say when Tiananmen Square happened before they were born.