Like everybody who was alive and alert at the time, I suppose, I have a million memories connected to 9/11.
I remember the surreal moment that morning when then-Mayor Jim Henry burst into a meeting at City Hall with the news that the Trade Center and Pentagon had been hit - and how everybody lingered for a few minutes, unsure what to do next. I remember thinking it sounded like a Tom Clancy novel.
I remember a few nights after the attacks, walking down Massachusetts Street when a jet plane flew low over Lawrence - and how everybody in my vision suddenly froze and looked up into the dark sky.
And I remember the generosity of Lillian Martinez.
As I've mentioned before, I got in my car a few weeks after 9/11 and started driving to New York; I needed to see history with my own eyes.
Along the way, I visited with the proud citizens of Knob Noster, Mo., where B-2 bomber flights were taking off for missions to Afghanistan. I stood in the field where Flight 93 crashed, talking with Tim Lambert, who owned part of the property.
Then I ended up in New York, where some college friends took me in and guided me throughout the city.
One of the places they took me was the small, brightly colored Bronx apartment where Martinez, a high school social worker, lived with her husband and children.
She told me how her students began to realize their city was under attack. She told me how her family gathered, that night, on the roof of the apartment building to watch the smoke billow out of Manhattan, to say goodbye to the Twin Towers.
And she served me a cup of coffee, flavored with a twist of lime. It was a taste I have not experienced before or since.
I wish I could better explain how that cup of coffee woke me up; that at the end of a car journey of more than 1,000 miles, I suddenly grasped that - to paraphrase a poet - America is large; it contains multitudes.
Growing up, I'd always heard the civics classes paeans to our country's melting pot diversity. But it wasn't until I saw with my own eyes that living in New York is different than living in Pennsylvania is different than living in Kansas that I came to have a visceral understanding of the subject.
We have, the last five years, been obsessed by the differences in Red America and Blue America - the Blues ruefully shake their heads at the "Jesusland" qualities of the Reds; the Reds just as disdainfully mutter about the Volvo-driving, latte-sipping proclivities of the Blues.
The subtext of all this, of course, is that the other side isn't "real" America. And that's utterly false.
No matter who you are, America - the land and the idea - is too big and too strange for you to own it.
It's a simple as a cup of lime-flavored coffee.