As schools and legislators struggled to come to terms with the unthinkable, one teacher in Muskegon, Michigan, thought to make a traditional Native American dreamcatcher to catch Columbine's bad dreams after its collective nightmare.
That teacher, Debra Gutowski, and her class sent it as a gift.
"Our hopes and dreams for it at that time were the same we have today," she told CNN. "For these shootings to stop."
But since Columbine in the spring of 1999, the dreamcatcher has been passed from school to school.
Each time, it meets a community devastated by tragedy, but bent on honoring those lost, by preventing the next school shooting. On March 16, the dreamcatcher passed to Parkland, Florida, and the Marjory Stoneman Douglas community, where 17 were killed by a gunman last month.
Columbine: Filling his son' shoes
Even in his worst nightmare, Tom Mauser would never have dreamed what happened on April 20, 1999, at Columbine High School
in Littleton, Colorado. On that day, Mauser recalls getting the news of his son's death in agonizing bits and pieces. He went to sleep that night still praying his son Daniel was alive, but knowing deep down, that he was almost certainly not.
"I broke down completely, crying down in the basement. My wife heard me upstairs," he recalls in a tone of voice that betrays he's told this story many times before.
But when asked about his son, a deep sigh suggests that talking about him hasn't gotten much easier. "Oh boy," he said, pausing before explaining, "I think he would be a medical researcher, trying to solve problems with illnesses. That's what he was leaning towards doing and I think he'd be great at," he said of Daniel.
A few days after the shooting, when Mauser's home was so full of floral arrangements that it looked and smelled like a funeral home, he suddenly knew what he had to do. A friend told him the National Rifle Association was, by coincidence, about to hold its national convention in nearby Denver.
"I thought back to the question that Daniel asked me about two weeks before he was killed," Mauser says. "Dad, did you know there were loopholes in the Brady Bill?" the boy had asked after a discussion with members of the debate team about the law that had mandated background checks for gun purchases except those sold at gun shows or online.
"Daniel asked me that question and then he was killed with a gun that was purchased through one of those loopholes," Mauser said. "I know why those loopholes are there. It's the NRA. Their convention is here. I've got to speak out."
Two days later, he found himself reluctantly addressing thousands of protesters. He had found a clear purpose, and plenty of supporters to help him.
"That gun-show loophole that existed in Colorado and in many states, we took that issue on first and we fixed it," he said of a statewide vote that took place after legislative inaction.
Now dressed in a brown jacket over a plaid shirt with blue jeans, Mauser looks like any man his age, with one exception: his shoes. The lace-up skateboard sneakers are the same ones Daniel was wearing when he was killed.
"I'd like to think that by stepping into his shoes that I am doing what he would want me to do," he said.
Thanks in part to Mauser's work, Colorado now requires nearly universal background checks and has limited the size of magazines to 15 rounds.
But even Mauser knows that gun control alone won't cure America's school shooting plague.
"No, we have to do a number of things to deal with the gun violence problem, and we're going to have to compromise, we're going to have to sit down and talk this out, and not scream at each other the way we are right now," he said.
Progress requires seeing things from someone else's shoes.
Red Lake: Glass, then a plan for change shattered
Six years after Columbine, the dreamcatcher was taken to Red Lake High School, on an Ojibwe reservation in northern Minnesota, after a student shot and killed five students, a teacher and an unarmed security guard
Missy Dodds was a math teacher, holding seventh-period study hall, when the shots rang out.
She had locked the door to her classroom and turned off the lights when the armed student showed up outside her door, which had a floor-length glass panel next to it.
"I looked up and I just so happened to see the 'aha' moment in his eyes when he goes like -- I can shoot this glass out," Dodds told CNN in her noticeably misplaced Southern accent.
She remembers three or four shots and then the sound of crunching glass as he walked into her room.
"He just started shooting and just went down the line. And when he got to me there was nothing left in his gun."
One brave student, Jeff May, was shot in the face after he attacked the shooter with a pencil. He survived. After that, the shooter took off down the hallway, leaving a shotgun on the floor.
Dodds never picked it up. She froze. Proof, she says that being armed that day might not have helped.
"But that's me, there are other [teachers] that are trained," she said, adding that the question of arming teachers should be left up to each school.
After the attack, Dodds tried and failed to convince state lawmakers to consider shatterproof glass in schools, something she says would have saved lives at Red Lake.
"I was literally blown off," she said of her trip to the state capital, St. Paul.
Dodds is still mad about what happened at her school. But she sees more clearly now how the system failed, and how the shooter, her former student, reached a breaking point.
"He lost his parents. He had told others he wanted to kill himself. Nobody seemed to care," she said. "No human being should have to go through what that poor kid went through."
Dodds quit teaching the following year, and struggled to regain any sense of normalcy. Many of her former students dropped out, one attempted suicide twice. Few made it through college.
Dodds revisited her classroom the day of the shooting to help identify bodies. Since then, she has often revisited that scene in her mind. Thirteen years later, she still struggles with post-traumatic stress disorder (PTSD), and pain she knows will never fully go away.
"There's been a lot of days when I haven't felt lucky. It's a burden I have to live with."
Sandy Hook: Seeking hands and hearts and minds
Red Lake kept the dreamcatcher for seven years. And then came the pre-Christmas 2012 massacre of the first-graders at Sandy Hook Elementary School
in Newtown, Connecticut.
Michele Gay lost her 7-year-old daughter, Josephine, that day. Like Tom Mauser's experience at Columbine, it took many hours to get the worst news of her life confirmed.
"My oldest daughter just couldn't accept it," she said, fighting back tears. "It just couldn't be. You know, she was sure that it was a misunderstanding."
But for Gay, the conversation was never going to be about guns. She even talked about it with her husband as he was trying to get back to Newtown in the very first hours after the shooting, before they knew Josephine was killed.
"He said 'everyone's going to go right to gun control,'" she said, "That's going to be where this conversation goes. And I remember just being surprised, like 'No, no, you know surely people will understand that there's a lot more to this than that conversation.'"
Gay, who now lives in suburban Baltimore, still cannot believe that the killer could send up so many red flags and yet have easy access to guns. But she has always focused on every other issue that could have prevented the carnage.
In 2013, a group of Sandy Hook parents fought for months to push lawmakers to enact sweeping gun control legislation. Gay was not among them.
She supports having the conversation about guns, but she's clear that there's no "easy button" to prevent school shootings.
She founded Safe and Sound Schools with another Sandy Hook mother, Alissa Parker. The pair, along with a network of survivors and experts consult with school administrators and help them create a customized safety strategy. No idea is off the table, even arming teachers.
"I know there are communities there that are doing it and doing it well," she said. "[But for] most of the communities that we're working with, there are so many other solutions that are less invasive, less expensive, less time intensive that they can employ before they even have to look at arming teachers."
Gay's apolitical approach is by design.
"If we go in and we start mentioning hot button issues or political arguments we suddenly divide the room in half. We lose half of the hands, and half of the hearts, and half of the minds that we need dedicated to the safety of the community."
The feathers of the dreamcatcher are meant to let good dreams through -- dreams that one day, the dreamcatcher will stay put, and that would be fine with Michele Gay.
"I really believe that it's possible that we could stop passing that dreamcatcher around. Or I wouldn't be involved in this," she said.
From Sandy Hook, the dreamcatcher was given to Marysville-Pilchuck High School in Washington
and then to Townville Elementary in South Carolina
. On March 16, Townville presented the dreamcatcher to Marjory Stoneman Douglas High School in Parkland, Florida.
But students there chose only to accept it for 17 seconds: one for each of the victims killed at their school. Then, they gave it back.
"I think their decision was very powerful," said Joanne Avery, the school superintendent for Townville, who presented the dreamcatcher along with the school principal.
Stopping the journey of the dreamcatcher, they hope, will just be a precursor to ending school shootings.