On a bright, sunny morning seven years ago today, I was sitting in my office in Boston’s Copley Square, getting back to work after I’d traveled to Cleveland for a wedding. My immediate concern was figuring out how to return a tuxedo I had rented in Ohio but didn’t have time to bring back before catching my flight. Could I FedEx it? What will it look like after I stuff it in a box?

Soon that became my least pressing concern. I glanced at the headlines on the news site I had in my browser — a plane had crashed into one of the Twin Towers. Terrible, I thought. What a freak accident. Then someone came running in my office shouting that another plane had hit the second tower. Immediately I knew it was no accident. Women were crying. We rolled a TV set out of a closet and turned it on to see the unforgettable, haunting images. Then we learned that the Pentagon was hit. America was under attack. Rumors of cars blowing up outside the State Department began to circulate.

I frantically tried to call colleagues in our New York office to no avail. All circuits were busy. There was talk that a marketing team from our company was doing a pitch not far from the World Trade Center. I started sending e-mails. News came that the flights had originated in Boston. There was, as is often forgotten today, a sense that the attacks on the Pentagon and the World Trade Center would not be the last. We evacuated our offices, which included several floors of Prudential Tower, Boston’s tallest building. We would evacuate almost daily for the next week as fools called in bomb threats, knowing we would have to take them seriously.

I actually considered staying behind for a while, but decided that the trains back into the suburbs might stop running and I did not want to be stranded in the city. The normally empty early afternoon commuter rail was packed with workers fleeing their offices to head home to their families. I sat next to a coworker. “How will know that this is over?” he asked. “How will we ever know?”