It only seems unimaginable to adults that many high-school students are just now learning the lessons of Sept. 11, 2001.
Unimaginable, maybe, that they are new to names like al-Qaida and the Taliban, to the horror of witnessing two jet airliners being swallowed by giant towers and walls of flame on the morning that nearly 3,000 people perished.
But the high-school children of today were, at their oldest, in second grade on that day. Some were not even in kindergarten.
And 10 years later?
"It's a historical event to them already," said Ray Curtis, Sentinel High School history teacher.
Many educators, including Curtis, are using the 10th anniversary of the attacks as a teaching moment for their students. Some, like Curtis, have begun elaborate multiday lessons on the subject, while others plan to interrupt their scheduled lesson plans for a discussion Monday.
How history teachers approach the 10th anniversary of the day most of us remember in chiseled detail is as diverse as the teachers themselves.
For Curtis, the lessons of 9/11 have needed reinforcement more and more each year as students are further and further separated from that day. And so he wants them to know not just what happened, but why.
"They don't know, but that's why we study history," he said. "For you and me, it was a pivotal event in our lives. But it's not to them."
Across western Montana, history and civics teachers say the same thing. Most of today's high-school students have only vague impressions of the terrorist attacks, their knowledge of its details and the complexity of Middle Eastern politics, culture and religion limited.
"They know it happened," said Big Sky High School history teacher Vicky Roche, "but you have to backtrack a bit and explain more than you had to even five years ago. ... When you talk to them and try to gauge their understanding, every year it seems like they're dwindling in their knowledge of it."
"Al-Qaida," Drew Burfeind said to the class, "is not a country. It is a group of militant, radical Islamists."
Most students in Ray Curtis' world history class know this, of course. But Burfeind, Curtis' teaching assistant, won't let any student be confused about the group responsible for killing thousands on a crisp September morning in 2001.
It is Thursday, three days before the 10th anniversary, the first day of lessons Curtis and Burfeind have in store for their students.
The 25 teenagers watched some video clips of the attack, none of its language censored as the first plane slammed into the south tower. They watched the video clip of President George W. Bush as he was given the news in a Florida schoolroom. They saw fireballs and suffering and death, none of it too graphic.
And they broke into groups, because they had some studying to do.
Curtis provided them with Missoulian sections from the day of 9/11, including the extra editions. He has also included papers from the first day of the Iraq war and the death of Osama bin Laden, among others.
He instructed the groups to read the sections and quickly improvise a news broadcast based on the content of each.
Here's how sophomore Sean Rawson delivered the news to the class.
"I've been told that there are 50,000 people working in the World Trade Center," Rawson said. "These planes hit within 20 minutes of each other. This is a huge terrorist attack. This is the biggest in our country so far. We also got news that there are two other planes. One hit outside of Pittsburgh and the other hit the Pentagon. We're not exactly sure, but we are suspecting Osama bin Laden is behind this attack."
The newscasts served as an introduction to the essential information of that day. Poring over decade-old newspapers, the students were doing exactly what most Americans were doing 10 years ago: trying to learn about a disaster and the people behind it - quickly.
The next day, Friday, these same students watched the PBS documentary "Road to 9/11," which put the attacks in historical, cultural and religious context.
In other words, the "why" of Sept. 11.
Some of that came from Burfeind as he peppered the students with questions.
"Why did they compare the attacks to Pearl Harbor?" and "Why would bin Laden be upset about America's support of Israel?" he asked.
Slowly, the students began to put the pieces together.
Curtis spoke about Bush and Vice President Dick Cheney's immediate vow to hunt down the "evil-doers."
"We weren't just going to go after terrorists," Curtis said. "We were going after countries that harbor them. What do you think that means?"
A girl quickly piped up.
"I think it means we're going to war."
Ten years ago, teaching about the terrorist attacks of Sept. 11 was easier than it is today.
Curtis was teaching at Big Sky High School in 2001, and after the attacks his students were hungry for knowledge about al-Qaida, bin Laden and American foreign policy.
"(A guest speaker) came to my class 10 years ago," he remembered. "It was homecoming at Big Sky and the students actually came into my class at lunchtime. There were probably 60 kids listening very intently, talking about what it means. It got their attention."
Quick too, said Hellgate High School history teacher Patty Hixson, were students about formulating opinions - even political ones - about the attacks.
"Right after 9/11, the political spectrum that was created was way far right for about three years," said Hixson, who had her master's thesis on women in Afghanistan approved by the University of Montana on the evening of Sept. 10, 2001. "I would ask them questions and line them up along a political spectrum. At first, they were far right. Now it's much more evenly distributed."
While time has softened their political opinions, it has also meant that students are entering high school with only vague information about the events of 9/11.
Knowing that has motivated Hamilton High School teacher Don Faris to annually discuss Sept. 11 with his history classes, interrupting his regularly scheduled lesson plans to do so.
"It's just like on Dec. 7," he said. "No matter what we are doing, we talk about Pearl Harbor."
He tries to coolly present the facts of that day, because there is danger in presenting merely the patriotic, pro-America position.
"I want them to have their understanding based on facts, not on premises or fear," said Faris. "For a long time, we were driven more by fear than we were by logic. I want what they know to be factual, not anecdotal."
Faris talks with his students about al-Qaida and bin Laden in a historical context, one that gives them "an understanding of where that mind-set comes from."
He is motivated to produce critical thinkers, not just about radical Islam but about American foreign policy and society, particularly "changes in security, the invasion of privacy, attitudes toward Islam and the Middle East, and misconceptions that we still have."
Faris believes his students need to be critical of the U.S. government in particular, because it has the power to send them to war.
"I want them to know," he said, "that there are times that what you are being told is not accurate."
Back at Sentinel High School, history teacher Jeff Nord has misgivings about driving home lessons on the 10th anniversary of 9/11.
And so on Monday, he will have a brief discussion about the topic and then quickly move on.
"I'll admit that I'm a little reluctant to mention it too much," said Nord, a longtime Sentinel teacher. "I will start the class by mentioning it and ask them about it. ‘What's the significance of yesterday?' My guess is that a great majority of them may not be able to answer that question."
So he will tell them if they don't know. But beyond that, dwelling on it has its own set of dangers.
"I guess a lot of it has to do with my personal feelings that yes, it was a horrible tragedy, but in some ways I think it's been misused to engender or create too much patriotism, if that's possible," he said. "For a lot of these kids, there's so much of that unthinking patriotism, and I try to temper it."
At Hellgate, Patty Hixson has seen the changes in attitudes and knowledge unfold over the past decade.
The way she sees it, her job is to give students good information not only about the events of Sept. 11, 2001, but the entire subject of the Middle East, war and U.S. foreign policy.
The Missoula County Public Schools District has begun an Arabic studies program, but Hixson said it could do more to get students to know about a region of the world, a religion and a culture that, for better or worse, have become unavoidably entangled in the lives of Americans.
"It's entirely possible," she lamented, "to graduate from high school in this district without one class on Islam, without anything that tells you one thing about that religion."
Americans in general have become much more informed about Islam and the Middle East, and she wants that for her students, too. But Hixson said she's careful not to inject her own opinions into the mix.
"My goal is always to get them thinking, and my slogan or motto is that good people disagree," she said. "I don't just say that - I really mean it. I think if you give information that is factual and good, they'll come to good conclusions themselves."
Telling students what to think is a disservice.
"If I told them," Hixson said, "I wouldn't be doing my job."
Reporter Jamie Kelly can be reached at 523-5254 or at email@example.com.