For many people in the United States it has now passed into the equivilent of ancient history.
For people born AFTER December 7, there is very little of the cultural or psychological impact that those alive at the time experienced.
My Grandparents could tell you exactly where they were when they heard about Pearl Harbor. It was something that was burned into their memory.
My parents (who were very young in 1941) can tell you exactly where they were when they heard about John Kennedy.
For both events, it's part of their life experience.
What about me? I wasn't born for either event. I was a history major in college, so I have a somewhat tighter connection with the events than do most people, but it's still not the same. It's something that happened pre-ME.
As those two generations slowly die off, Pearl Harbor and Kennedy's Assassination will take their place in the annals of American history as events for which no living memory exists.
Why don't we celebrate the end of the Civil or Revolutionary Wars as they did 100 and 200 years ago? Because all living links to those events are long dead.
Our generations have a different set of cultural hallmarks...
For me, there's Three Mile Island, the Reagan Presidency, and of course September 11.
But how can I convey to the next generation, those who weren't alive, a truly empathetic vision of how I felt during those times? How can I adequately explain to, say, mtnbkr's daughter, who's now going on 3, just how I felt when I crested the hill near my house and saw the smoke from the burning Pentagon just a few miles away?
The simple answer is... I can't.
No one can invest in someone a cultural or psychological legacy for events that they didn't witness.
That's what history is.