Fifteen years ago on Sunday, the United States of America came to a screeching halt. Everything stopped, suspended in a moment in time unlike any other. These events were of equal atrocity to the attack on Pearl Harbor; and like the explosion of the space shuttle Challenger, they were committed to video to be played and replayed. The attacks on Sept. 11, 2001, were magnified by the sheer enormity of the acts of terror perpetrated in New York City, Washington, D.C. and in the air above the pastureland of Pennsylvania, and by everyone’s ability to watch it happen, over and over again.

There are certain events that solidify in time and memory: Pearl Harbor, the assassinations of Dr. Martin Luther King Jr., John F. Kennedy, Bobby Kennedy, the Challenger explosion, 9/11. They become a universal experience, a topic of conversation, where all can share stories of where they were, what they were doing, what the life around them looked like then and how this event would ultimately impact that day — how it would impact their lives.

They are shared experiences, though each one is slightly removed from the next. On Sept. 11, 2001, many Americans experienced the aftermath of the attacks in the comfort of their own homes, watching the television, anxiously seeking knowledge that would explain the horrendous acts that unfolded from the moment American Airlines Flight 11 crashed into the North Tower of the World Trade Center at 8:46 a.m. Others gathered around classroom TVs, the ringing of bells ignored and classes suspended in time, while teachers struggled just as hard as students to comprehend this new, inconceivable lesson. They were at home, at school, at work. Others were just as far away, yet closer, as they frantically sought information about loved ones who were supposed to be on that plane or in that building. Still others were closer, able to watch the incomprehensible play out right before their eyes — eye witnesses to what no one would have believed possible. There were those even closer, who ran through the ash-filled streets of lower Manhattan, choking and blinded by the dust of what once was and in a moment’s time was no longer.

And then there were those who were so close they will forever be linked to that day. Because for 2,996 people, that day was their last.

So many different experiences of the same event exist, each branded in memory, each exclusive to its owner. But of those unique experiences, whether near or far, observer or mourner, televised or in person, a new experience was created on that day — an American experience.

One we will never forget.