Americans have intimate memories of Sept. 11, 2001. Many can recite, in detail, where they were and what they thought and felt when they saw or heard that New York City's twin towers fell, the Pentagon was attacked and a hijacked plane had crashed in Pennsylvania.
Many students, particularly younger ones, do not know who Osama bin Laden is, or lump the day together with other American tragedies, like the Pearl Harbor attacks, without understanding the direct effect Sept. 11 has on their lives.
Students talked to the Times about what they have learned about the attack in their school career, some talking about the day as if it were in the distant past.
"It's a seminal event in our nation's history," said Mike Chrvala, a teacher at Shiloh Middle School, who taught a class about Sept. 11 at Friendship Valley during the first session of the Carroll County Summer Enrichment Program. "Our nation has been at war all of their lives and [students] could not articulate why."
Chrvala also teaches about Sept. 11 as part of his history classes during the school year as well. He said he wants students to know what it felt like to view the events that day and better understand the cause of the attacks. He is planning on building a curriculum teachers can follow to teach about Sept. 11, he said.
Westminster High School junior Greg Merrill, 16, was in kindergarten on Sept. 11, 2001. He remembers that he was let out of school early, but did not understand why. He said he knows a lot more about the day now, as it is sometimes discussed in classes around the day's anniversary.
He knew a lot of the details of the attack - that the men involved used box cutters to hijack the planes; that the Pentagon was attacked as well; and another plane was hijacked and crashed in the Stonycreek Township in Somerset County, Pa. But he needed to be reminded by his group of friends that the attackers were, indeed, Muslim.
He was more profound when he was reminded of the terrorists' religious affiliation.
"Everyone has different views of what is going on," Merrill said. "Some people [say] 'All Muslims are bad.' Obviously that's not true."
Sam Hitt, 16, a junior at Westminster High School, said the attack has mostly been discussed around its anniversary. When it is brought up in class, it is mostly a group discussion, which allows students to give their view on the events, he said.
He said he is still a little fuzzy on why al-Qaida attacked the U.S.
"I am not 100 percent sure on why it happened," Hitt said.
Doug Stuart, chair of International Studies at Dickinson College in Carlisle, Pa., said students have told him that their teachers before college have generally allowed for students to lead discussions on Sept. 11. He said teachers often provide anchor points for students to keep the discussion going.
He said he thought this was a good approach to the subject, as there may be a diverse set of students in the classroom. Some students, for example, could have family that died or were otherwise affected by the attacks.
"I thought that was kind of interesting," said Stuart, who previously ran a website that contained lesson plans and resources for those teaching Sept. 11. "It shows sensitivity and the multiplicity of people who may be in the classrooms."
He said having discussions of how the attacks compare to other historical events, or how they can be connected to current events, is also a good way to teach a lesson on the subject.
Adam Fairchild, 13, who was in Chrvala's history class last year, said learning about 9/11 was eye-opening. He and some other students visited the National September 11 Memorial and Museum in New York as part of the class. He said he feels he has a much better understanding of the attack.
"After the field trip ... you feel like you can relate," Fairchild said.
Stuart said the subject is challenging to teach about at this point, since it may be too early after the event to understand how it will change the country.
"It's still a little too soon to say how we are we transformed by Sept. 11," he said. "But I think we can [say] we were transformed."