My older daughter, J, is about to turn 16 years old. An 11th grader at a well-regarded public high school (and my alma mater), she often claims that school is "boring" but her grades are mostly quite good. She is an accomplished guitarist who has played solos and duets in school concerts, as well as participating in school musicals. She loves heavy metal rock and roll, local sports teams, and hanging out with her friends. She has attended Young Judaea sleep away camps for six summers, and already hopes to go on Year Course in Israel.As a high school junior, she is studying United States History and Government this school year, a course I have taught many times during my 20-year teaching career. One of the final topics in the "USHG" curriculum is the terrorist attacks of September 11, 2001. And while she claims not to remember it first-hand, she did witness it.The morning of 9/11 she and I were driving in Brooklyn, New York, to attend the first day of a cooperative playground in the Fort Greene neighborhood. I had heard on the radio news that there was an airplane accident and fire at the World Trade Center, and was rather baffled. When we stopped for a red light at Atlantic Avenue and Vanderbilt Avenue, I could see immensely huge orange flames, as well as black smoke, hovering in the horizon. They were coming from lower Manhattan but seemed so close. I knew immediately that the airplane accident was no small event. People were stumbling around in the road and on the sidewalks, holding their heads, crying, saying things such as "I can't believe this!" I looked at the sky, I looked all around, and I could barely believe what was going on.And I know that J must have seen some of this but not understood it.The past few days our newspapers have been covering 9/11 memorials, testimony and other related stories. There has been coverage of how 9/11 is taught in schools; one article uses the phrase "To them, it's history, just like Pearl Harbor" in its title. But for those of us who are lifelong New Yorkers, and anyone who lived in New York and nearby counties of New Jersey, 9/11 is something that looms large in our lives. J is one of those students who was a witness to this horrific day.An Orthodox Jewish man in our neighborhood died at the World Trade Center, Abe Zelmanowitz. A member of our synagogue died there too, Lisa Weinstein. I had known her since I was in 6th grade, she in 5th. I have told J and her younger sister about both these people. We have attended memorial services and visited the outer area of the WTC 9/11 memorial. My intention is that my daughters realize the impact this terrible day and its aftermath have had on our lives, our nation, and much more. But it is difficult, even if they are New Yorkers, for them to grasp fully the import of the day. However, they did live through Hurricane Sandy of late October 2012, and that seems to be the most serious event that they can recall, because they witnessed it. They saw it, they heard the rain and the winds, they saw the uprooted trees and cars propped up on mailboxes and benches along Ocean Parkway.We Jews are supposed to experience elements of our way-back past through observing holidays. The Passover seder is supposed to achieve elements of this. The Martyrology service of Yom Kippur is meant to conjure up this. Holocaust memorials and observances are intended to do this. But it is very difficult, really, to do this. It is hard for our children to truly grasp what happened on 9/11. Yet we have the duty to teach them about it.