"I went to my principal and said, 'You might have to fire me, because how do you not teach kids about what happened yesterday?' " Chrvala recalled. "People talk about how Sept. 11 was this generation's Pearl Harbor. You've got to teach it."

The school system changed its philosophy, and Chrvala is pleased that his students have shown interest in the topic. He also realizes that it may initially be difficult for them to grasp how the attack on America was unique.

"They're very attentive," Chrvala said. "They understand that the attacks were an act of war. They also realize that in past wars we always battled other nations. When we fought World War II, we were against the Nazis from Germany and the forces from Japan.

"But where is al-Qaeda? They're not from one place, and that is how the world has changed," he said.

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Chrvala's fear of heights drove him away from firefighting as a potential career, and he became a teacher instead. He still thinks about how his life could have been different if he had joined one of the firehouses in northern New Jersey … or Manhattan.

"I learned about those guys that went into those towers," Chrvala said. " The memorial bracelet that I wear has the names of the 11 guys in FDNY Rescue 1 who were lost in the attack."

Chrvala, who lives in Towson with his wife and two children, will help to commemorate the 10th anniversary of the 9/11 attacks this weekend.

On Sunday, Sept. 11, the Shiloh Middle School History Club is hosting the Never Forget 5k-one mile run at North Carroll High School, also in Hampstead.

"We wanted to do something for our local heroes," Chrvala said of Sunday's events. We're supporting the Hampstead fire company — people who put it on the line every time they go out."

Then, on Monday, Chrvala and his students will host "Remembering 9/11" at 6:30 p.m. at the Finksburg Library in Carroll County, discussing their journey to the trade center site and their meetings with families of those who died on 9/11.

Shiloh Middle is also involved in the Hats for Heroes project. To mark the 9/11 anniversary, students were invited to wear a hat during the school day in exchange for a $1 donation. Proceeds benefit the Fire Department of New York's Rescue 1 unit, and the Stephen Siller "Let Us Do Good" Children's Foundation, in honor of the fallen firefighter.