Some memories are etched so strongly in the mind. When I close my eyes, I am back in that day.

A cool, crisp September morning. The kind of New York day where you grab a sweater as you leave your apartment, knowing you’ll peel it off as the sun rises in the sky.

I brought a change of clothes with me to work that day, with plans to go to the Yankee game that evening. The game never happened.

I was 26 years old, a year out of law school, working hard in a top law firm, on that clear blue morning when ashes filled the sky and chaos and confusion rained down.

The world can change in an instant. My illusion of America as a safe haven was shattered.

Terrorist attacks happened in the middle east, not in New York City. Even though it had before.

I knew things would be different forever. But I didn’t know how I would be different.

The Body Remembers

At the time, I didn’t know anything about trauma or what happens to the body when it experiences an event like 9/11 and the immediate aftermath of uncertainty. And even if I knew, I don’t think I would have considered my experience to be a trauma. I was lucky: I didn’t have to run for my life, trying to escape a building as it crumbled to the ground.

If you had told me then that any crisp autumn day with a clear blue sky would trigger my memories of that fateful morning, I wouldn’t have believed you. If you had told me that the memory would live in my body, I would have thought you were from another planet. I was so disconnected from my body. I didn’t know it was recording every experience.

What I know now, still in the toddler stage in my study of trauma and the nervous system, is that everyone in New York City that day experienced a trauma, albeit at different levels.

The Trauma Body

I recall how, on that day and in the subsequent days, I was constantly bracing in preparation for the next attack, wondering if a plane would take down the midtown building where I worked. I started to keep a pair of sneakers in the office, just in case. The experience of “exaggerated probabilities of danger” is part of PTSD.

At the time, I couldn’t imagine that moment forward my body would seize in fear anytime I saw a plane that seemed a little too low in the sky, a siren wailed, a helicopter chopped its blades overhead, or I saw smoke rise from a building.

I couldn’t conceive that almost 20 years later, even if I wasn’t in New York, I would feel the heavy weight sitting on my chest and choking my breath, the churning of my stomach, the aches in my lower back.

Last year, living 3,000 miles away, with no blue lights to remind me, how did I know it was 9/11?

My body told me.

You Don’t Need an App For That

We have so many apps to help us remember things that want to remember but that we forget. But we don’t need an app to help us remember the important or impactful things.

The body remembers.

It remembers in subtle ways we don’t always notice, unless we are paying attention.

The way my heart skips a beat when a plane flies too low or the way my stomach knots when a helicopter flies overhead, or the way I hold my breath when sirens wail.

Life went on. New Yorker built a new downtown. The Pentagon was repaired. We all adapted to new security protocols when traveling. A generation of children have learned about 9/11 in history books as a thing that happened a long time ago.

But for those of us who were there, we couldn’t forget if we tried.

The body remembers it all.