It’s hard — almost unfathomable — to imagine that more than 15 years have passed since Sept. 11, 2001.

Anyone who was older than a toddler then remembers the horrors of that day. The stunning blue sky. The cascade of increasingly incomprehensible news. The hours spent transfixed in front of TVs. The numbness of the weeks that followed.

As the Twin Towers fell, I braced myself for immense losses in Westport. Miraculously, the numbers were nowhere near as high as I imagined they would be.

But of course we did not escape unscathed. Several Westporters — Staples High School grads and residents — were among the nearly 3,000 people killed that day.

Their names and lives live on in the memories of all who knew them. They, and a few dozen other Connecticut citizens, are remembered at Sherwood Island. Connecticut’s oldest state park is the site of a “living memorial.” The site was chosen for two reasons: its beauty, and its proximity to New York. In 2001, visitors to Sherwood Island saw smoke billowing from Manhattan. The park was ready for us as a staging area. Sadly, rescue operations were never needed.

Over the years, conditions at the 9/11 memorial deteriorated. Weeds and underbrush grew. Goose droppings piled up.

But last week, just before the official ceremony, something remarkable happened. In a display of unity and action reminiscent of the days following the terror attack, volunteers took up the cause. The Friends of Sherwood Island group marshaled resources to clean the area. Westporter Tony Palmer dispatched his landscaping crew; they spent two days, gratis, at the site. By the time Gov. Malloy and other officials arrived for the annual rite, the memorial sparkled and shone.

I was not able to attend. I don’t know how many local people were there. But I do know of one with a special connection to 9/11.

Hillary O’Neill was born that day. Her father (Coleytown Middle School teacher Glenn O’Neill) and mother (landscape designer Heather O’Neill) had mixed emotions 15 years ago. As they welcomed their second child into the world, TVs showed destruction all around. Outside the delivery room, Norwalk Hospital staff members prepared for victims who never came.

Hillary has turned her infamous birth date into something positive. Every Sept. 11, she volunteers for a good cause. She follows the lead of people decades older, who felt similarly years ago. Devastated by the magnitude of what they’d seen, they found solace and meaning in little actions. Magnified by millions, Americans managed to turn tragedy into something at least bearable.

It did not take long, unfortunately, for that spirit of volunteerism to wane. Our warmth toward strangers, our willingness to embrace differences, our urgency to act — faded much more quickly than the physical and emotional scars in downtown Manhattan, the Pentagon and Shanksville, Pa.

There are many reasons why Americans no longer feel the solidarity that brought us together in autumn 2001. A war based on what we now know were dubious justifications helped erode that sense of purpose. Other politics played a part. So too did the passage of time.

Fifteen years later, we remain involved in a war on terror. The enemy has changed. Saddam Hussein is just a memory; now we focus on ISIS. We’ve weathered anthrax. We’ve grown accustomed to taking shoes off in airports, and packing toiletries in Ziploc bags. We’ve learned that Americans are not the only targets. Anyone — in Brussels, Paris, Nice, you name it — can be attacked.

Westporters did not die in enormous numbers on 9/11. But we did not escape the carnage. Many of us knew people who were murdered on that day. Nearly everyone knows someone with a story. A meeting at the World Trade Center that miraculously was canceled. The sudden view of a plane, while climbing the subway stairs. The harrowing trip home that miserable, endless afternoon.

What most of us don’t know, however, is someone who has actually served in the war on terror without a military draft. Our all-volunteer army is filled with men and women from places not at all like Westport. Multiple deployments in the longest conflict in American history are served by people we don’t know, or even think about.

Television brought Vietnam, a war that divided our nation, into our living rooms each night. The latest internet sensation and social media meme now divert our attention from Iraq and Afghanistan. Those life-and-death battles are out of sight, out of mind.

In Westport, 9/11 is much more tangible than the “war on terror.” Yet, like the memorial at Sherwood Island, we must take concerted, concrete steps to make sure its memory and meaning do not become overgrown and defaced.

Dan Woog is a Westport writer, and his “Woog’s World” appears each Friday. He can be reached at dwoog@optonline.net. His personal blog is www.danwoog06880.com.