They remember their parents coming early to scoop them up from school that day. And the television channels that were changed quickly so they didn't see the planes hitting the towers, over and over again.
So they sat in their social studies classroom at Centreville (Va.) High School this week, ready for a history lesson about the day America was devastated, back when they were just third-graders.
That day is hazy for many of them. It is a news item, a reference point. A weird, frightening, divided world so far from their own.
So far, they are not hating. Unlike so much of America today.
This week, these kids in northern Virginia gathered for class at their diverse school, their faces reflecting the global hot spots that their parents fled — North and South Korea, Pakistan, Albania, Afghanistan.
Two Sikh boys with turbans, huge backpacks, sagging board shorts and iPod earbuds hanging from their necks shoved each other as they got off a bus. The girl with a hijab and a leopard print bag plopped down at her desk, gabbing with her friends.
They seem relatively oblivious to outward differences.
Nine years ago, things weren't so friendly in the lunchroom at many schools.
"At first, right after the attacks, I'd hear it in the hallways and stuff. Some of these kids, the Muslims, would get teased, called terrorists," said Joseph Radun, who is teaching at Centreville but was working in Arlington, Va., on Sept. 11, 2001.
The attacks were raw and horrible for his students back then. And the anger and fear were palpable, Radun said.
"People would call me a terrorist, said Megan, 18, who left Afghanistan when she was 4 years old and is now a senior at Centreville High. "But I'm, like, more American than I am a girl from Afghanistan. I mean, I've been in America way longer."
For the most part, today's teens seem to view Sept. 11 as gauzy history.
In his class, Radun serves up a rat-a-tat, in-your-face lesson about the attacks.
"You've gotta know what really happened. What it was like that day," he told the students. "The radicals? If they could, every day would be like Sept. 11 in America."
He tried to use the day to explain the civic values of courage, respect, perseverance, responsibility, justice, initiative, moderation and integrity.
They talked about national security and the USA Patriot Act. Not a single student condemned Islam. No one turned to look at Megan in her hijab.
If kids can get it right, what happened to us?
America, as a whole, was at its best right after the attacks. Our nation didn't repeat history's atrocities with the callous internment of Japanese-Americans after the attack on Pearl Harbor.
Then, and in the years come, President Bush tried to calm Americans and quell hatred.
But fueled by the painful debate over a mosque and Islamic center planned for Manhattan near ground zero, a Washington Post-ABC poll conducted last week found the country's mood toward Muslims increasingly hostile.
The poll said that 49 percent of Americans view Islam unfavorably.
"I don't understand that. I didn't do that. My family didn't do that. All the Muslims didn't do those attacks," Megan told me in the hallway after class.
I think 49 percent of Americans need a lesson from the kids at Centreville High.