Today is the 11th anniversary of 9/11. And three months later, we will mark the 71st anniversary of the Japanese attack on Pearl Harbor.

The two worst attacks on American soil each resulted in nearly 3,000 deaths and led the nation to war. Still, given the passage of time, Dec. 7 will be noted with minimal, if any, reverence by most Americans; and, despite little more than a decade having lapsed since 9/11, already some memories are fading too fast.

How else to explain a New York Post story last week detailing how some visitors are treating the National September 11 Memorial in Manhattan as a “playground”?

The Post reported that “tourists balance coffee cups and soda bottles on the parapets bearing the names of the dead. Parents hoist their children to sit on the bronze plaques, while other visitors splash water from the two waterfalls onto their faces to cool themselves on a hot summer day. On the plaza, tourists break out lunch foods and lie on their backs.”

That behavior is appalling.

Those who would picnic in a graveyard disrespect not only the lives that were lost on that sacred ground, but also those soldiers still in harm’s way as a result of the events that gave rise to that memorial. Such behavior, however, is in keeping with a pattern.

Despite the best of intentions, too often we do forget too soon.

April 19 marked the 17th anniversary of the Oklahoma City bombing, the day on which 168 innocents, including 19 young children, lost their lives.

One day later, April 20, was the 13th anniversary of the Columbine school shootings, in which 12 students and one teacher were murdered by two students who then killed themselves.

In Philadelphia, May 13 marked the 27th anniversary of the MOVE conflagration that claimed the lives of 11 people, five of them children.

Ever heard of Harold Unruh? Wednesday was the 63rd anniversary of the day Unruh murdered 13 of his neighbors in Camden, N.J.

And come Nov. 22, the nation will mark the 49th anniversary of the assassination of President John F. Kennedy.

Each of these was a monumental day based on tragedy, but for how many of them do we now pause?

All were events that were “the” news for a period of months, and, in every instance, grieving was accompanied by the refrain of “never forget.” But life does go on. And when witnesses and loved ones of the victims die and memories fade, the challenge of remembering grows more difficult.

Ensuring that Sept. 11 stands apart will require community and individual action, and churches should note the coming anniversary.

Today, 9/11 should be part of every school’s lesson plan.

Employers should find a way of noting the occasion, in keeping with the decorum of the workplace.

Flags should, of course, be flown at half-staff.

And the media must keep showing the harrowing footage of the airplanes hitting the Twin Towers. More than anything else, if that presentation were shown with more regularity — beyond just the anniversary newsreels — it would go a long way toward keeping us ever mindful of what transpired 11 years ago.

Most important, at dinner tables across America, tonight needs to be a time for parents to share with their children the perspective of where they were 11 years ago, what happened to the nation, and with what consequence.

We won’t forget. But unless we take these measures and more, those who follow us will.

Michael Smerconish writes for The Philadelphia Inquirer. Readers may contact him via www.smerconish.com. This essay was distributed by MCT Information Services.