ATLANTA It was about three years ago, the first time Jerry Swiatek got to the 9/11 portion of his social studies class and had some freshmen say they'd never seen footage of planes flying into the World Trade Center.
Each year since, more students among the current 15-year-olds tell him the same thing, leaving him amazed that they've never experienced the horror of watching the twin towers collapse.
It's etched forever in the minds of their teachers, but for most school children, Sept. 11, 2001, is a day of infamy they don't remember.
This year's high school seniors were in second grade a decade ago. Their memories of the day of the attacks are fuzzy at best a teacher crying while hugging a colleague or being shepherded into the auditorium away from televisions. For younger kids, it's an even more distant event.
"They've heard about it, they are aware of changes that have taken place in our country, but their parents have never let them see the footage," said Swiatek, who teaches mostly high school freshmen in rural Citrus County, Fla., and shows news clips of the burning towers to shocked students each year around Sept. 11. "Students who had never seen it couldn't believe what they were seeing. I was a little concerned."
More than 60 million children in America are 14 and younger, according to the U.S. Census Bureau. So how do teachers handle the task of explaining 9/11 to students who don't remember when anyone could walk right up to the gate at the airport or when Osama bin Laden wasn't a household name?
The answer isn't simple, and it has changed over time.
Students across the country will gather for assemblies, hold moments of silence and spend history and social studies classes focusing on Sept. 11 this year. They'll hear stories from teachers and talk to survivors or family members of victims.
They'll read front-page headlines screaming "UNTHINKABLE" or "ACT OF WAR" in giant letters.
Though it's been a decade, just a few states and school districts have a set curriculum for teaching Sept. 11. Unlike Pearl Harbor or the assassinations of Martin Luther King Jr. and President John F. Kennedy, the story of 9/11 is still being written.
New Jersey unveiled its new curriculum this year in honor of the 10th anniversary of the attacks, a lesson plan created by families of Sept. 11 victims and the New Jersey Commission on Holocaust Education. It provides 56 lessons which start simple and grow in complexity and maturity with each grade level emphasizing the good that came out of the tragedy for younger students and examining the history of terrorism and other lessons for older students.
The lessons recommend some kind of action, such as creating art about tolerance or service projects to honor or remember victims.
"We really wanted something broader in scope, that Sept. 11 would have a context to it," said Donna Gaffney, a co-founder of the 4 Action Initiative, which put the materials together.
In 2009, New York City schools launched what was believed to be the first comprehensive educational plan focusing on the attacks. Created by the New Jersey-based Sept. 11 Education Trust, the curriculum has also been tested in schools in California, Alabama, Indiana, Illinois and Kansas. It uses videos and interviews about the attacks, as well as interactive exercises like having students map global terrorist activity with Google Earth software.
New York City announced an updated Sept. 11 curriculum this month that includes tips on how to help students cope with learning about the horrors, a study of the art inspired by the attacks and a history of the 9/11 memorial.
A few nonprofit groups like the Sept. 11 Education Trust founded by Anthony Gardner, whose 30-year-old brother, Harvey, died in the World Trade Center have come out with lesson plans but those programs have not become widely adopted. Even the U.S. State Department has developed materials.
"It's a long process to get the program out there in the hands of teachers and making teachers feel equipped to handle it with students," said Gardner, who said his curriculum is used at least in part in about 2,000 schools across the globe. "Maybe by the 25th anniversary there will be programs in place that meet the need."