For some students, Columbine created an undercurrent of anxious jokes and banter. Wakefield told me that the Columbine shooting was a consistent subject of conversation among his middle-school peers (until the September 11 attacks, after which “that was all we talked about,” he said). “A lot of it was talking about what we would do if there was a shooter in the room, what we would say if they had a gun to our head,” he said. “A lot of middle-school-level bravado: ‘Oh, yeah, if a gunman came after us, we’d just karate-chop them in the neck and we’d save the day. I’d be great—we’d take the gun from them and then we’d be the hero.’”

The joking and bluster sometimes gave way to real fear. Wakefield said that he and his classmates would talk about the design of their school buildings, “loosely planning what would happen if there was a disaster like this.” When he started at a new middle school in ninth grade, he analyzed the school’s structure with his friends. “There’s more corners that we can hide behind” compared with his previous school, he remembered discussing. “If we can make it to the parking lot, we can hide behind a car or something. There’s lots more cover here.”

The Columbine shooting led some students to grapple with violence that already existed at their school. Westendorp, who went to high school in Minneapolis, remembered that at first the shooting felt “a little bit more removed.” But then a teacher “sat down with us,” she said, “and she’s like, ‘People do bring guns to school. We’re here to keep you safe, but you’re not immune to this. It could happen. It could happen anywhere.’”

Katreena Lloyd-Williams, who graduated from high school in 2002, remembers that at Audenried High School, in South Philadelphia, where she went for part of her freshman year, metal detectors were in place before Columbine. “That school was kind of known in the neighborhood as not the bad school, but a bad school,” she told me. “There was always something going on there.” Even so, Columbine changed how Lloyd-Williams thought about the dangers of going to school. “The violence that happened in the school, it was something that was very personal,” she said. “You knew if you weren’t fighting with somebody, then you weren’t going to be a target. When I thought about Columbine, it in a weird way took away that peace of mind. You realize: Okay, so somebody could just be pissed and come in and shoot everybody. I never thought that way. I just thought, Oh, I keep my head down, I mind my business, I’m good. That definitely freaked me out a little bit.”

Still, the Columbine shooting felt “removed,” Lloyd-Williams told me, “because it was across the country, [and] a mass shooting wasn’t so common” at the time. Today, she attends Temple University as an adult student, and she thinks about the risk of a shooting much more often. “That’s so in my head when something happens. Oh my God, this is a big campus, there’s a lot of kids here, anything could happen. And I know that I didn’t think about that before.”