Tragic events seem to become collective milestones in our lives.

Think of the deadly terrorist attacks of Sept. 11, 2001, and it is easy to look at that date as a dividing line between what once was and how we live now.

For millions of Americans, the attack on Pearl Harbor on Dec. 7, 1941, delivered the same type of feeling. The attacks by the Imperial Japanese Navy sank four battleships and damaged four others. The day pushed America into World War II and set the stage for a long, bloody ordeal in the Pacific that ended only when atomic bombs were dropped on two Japanese cities in 1945.

The attack on Pearl Harbor held a prominent place in the American collective consciousness for decades. More than 2,000 Americans were killed in the attack, a butcher’s bill that would not be replicated until 9/11.

The day symbolized so much for so many for so long across the nation but, 80 years later, its significance and impact has faded. Most of the people who fought that day and survived have passed on. The generation that lived through the attack also is depleted by death, and with their passing the meaning of the day — the sacrifice, the bravery — has faded as well.

Now, as a nation, the 9/11 attacks are the most recent national tragedy, and we remember that terrible day with respect and honor each year — as we should.

I hope, though, that somehow Dec. 7, 1941, doesn’t become just another date. It shouldn’t. That’s because the day illustrates the American quality of resilience, of being able to respond to adversity.

The bombing of Pearl Harbor caught the United States unprepared for war. The attack shoved the nation out of the Great Depression and put it on a path to war and, after the guns went silent, to decades of economic growth.

The nation rebounded from the attack, went on the offensive and emerged from World War II triumphant.

What I hope we don’t forget, though, are the brave acts of the men on that fateful day. Many of them died. For their sake, and really for the sake of our country at large, their sacrifice should not be allowed to fade away into the pages of history.