Three years ago, I wrote about this: How big a day December 7 was, for much of my life, as Americans remembered Pearl Harbor — the surprise attack in Hawaii that took the U.S. into World War II.

And, mostly, I haven’t changed my outlook … how time and current events conspire to push notable days back and down … to the point that the New York Times’s website today relegated Pearl Harbor to the mention it got in the “Today in History” feature provided by the Associated Press. Even 15 years ago, it would have been noted by a story in every American newspaper.

Today, I was left to muse over the concept of each generation having a day or two of “fame/infamy” … events which remain seared into memories … but which within X number of years are replaced by two or three more recent upheavals.

For instance Pearl Harbor and D-Day (the Normandy landings in the same war, June 6, 1944) had a long run as remembered days.

Now, however, they are pretty much eclipsed by terror events, particularly September 11, 2001. And maybe some residue from the John Kennedy assassination, November 22, 1963, an event still shrouded in controversy.

Could we see other dates rising and then fading from memory, as we go back in time, through American history?

Before Pearl Harbor, perhaps it was Armistice Day, November 11, 1918, ending World War I … and perhaps the date (February 15, 1898) the heavy cruiser Maine blew up in Havana’s harbor.

To the generation that came before, it might have been the day Abraham Lincoln was assassinated (April 14, 1865) … or even the day that Confederate general Robert E. Lee surrendered the Army of Northern Virginia at Appomattox Courthouse, effectively ending the Civil War, only five days before.

And before that?

Maybe the Alamo (which, like the Maine, Americans were encouraged to remember), where on March 6, 1836, a few hundred Texas rebels were killed to the last man by the army of Mexico, an event that precipitated Texas breaking away from Mexico and soon after joining the United States.

Or would they have skipped back to the Battle of New Orleans (January, 1815), where Andrew Jackson defeated the British at the end of the War of 1812.

And before that? Maybe the death of George Washington (December 13, 1799) resonated for 20 or 30 years … or the British surrender at Yorktown, which came on October 19, 1781, and effectively ensured the United States would be a free and independent country.

And we could go further back – the July 4 Declaration of Independence, in 1776, the Boston Massacre, the Battle of Bunker Hill, etc.). Maybe all of these were remembered by regular folks, back then, and remarked upon by newspapers for several decades.

(July 4 has been straight through American history, making it the one exception to “eventually we forget”.)

It’s just the way the human brain works. Big events we lived through … we are likely to remember. But when we pass from the stage, following generations are likely to focus on major events of their own lifetimes.

It’s like a slowly revolving door of historic turning points. But only two or three events at one time can hope to remain on center stage.