The heartache of the 2018 shooting that unfolded at Florida's Marjory Stoneman Douglas High School is present in the halls of so many schools across the country Thursday.
A number of schools in Florida, particularly those close to the scene of the Feb. 14, 2018, shooting, were holding memorial events and moments of silence to remember the 17 students and staffers who were fatally shot in the attack.
Marjory Stoneman Douglas students who decided to attend school on the anniversary will not be sitting in the classroom like normal; they will be working on service projects in honor of the lives that were lost, The Associated Press reported.
Many of the students wore maroon T-shirts emblazoned with the hashtag #MSDStrong -- a phrase shared so often in the wake of the shooting.
A handful of Parkland students who have spent much of the last year advocating for gun reform -- including the student leaders who became national figures based on their organization of the March For Our Lives demonstration -- won't be speaking out.
The student leaders, like David Hogg and Delaney Tarr, noted on Twitter that they would be "going dark" from Feb. 14 to Feb. 17.
"Please remember the people we're stolen from us that day; they are why we fight for peace," Hogg wrote in a tweet on Wednesday.
President Donald Trump issued a statement paying tribute to the victims.
"One year ago today, a horrific act of violence took the lives of 14 students and 3 educators in Parkland, Florida. On this somber anniversary, we honor their memory and recommit to ensuring the safety of all Americans, especially our Nation’s children," he wrote in the presidential message issued by the press secretary.
In the message, he also described the "tremendous strides" that he says his administration has taken to address gun violence in the wake of the tragedy, including his signing of the STOP School Violence Act which allots funds toward prevention efforts and the Fix NICS Act which improves gun registration reporting efforts.
"Today, as we hold in our hearts each of those lost a year ago in Parkland, let us declare together, as Americans, that we will not rest until our schools are secure and our communities are safe," he wrote.
Former President Barack Obama also took a moment to reflect on the work that survivors have done in the past year.
"In the year since their friends were killed, the students of Parkland refused to settle for the way things are and marched, organized, and pushed for the way things should be - helping pass meaningful new gun violence laws in states across the country. I'm proud of all of them," Obama wrote on Twitter.
Some of the most moving tributes came from the parents of the slain students, including Andrew Pollock, the father of 18-year-old Meadow Pollack. He tweeted that "everyday hurts" and vowed to continue his work to reform gun laws.
"Meadow, my life will never be the same without you, but I’ve been fighting everyday to make sure this never happens again. I promise you I’ll #FixIt," he tweeted.
Max Schachter, that father of 14-year-old Alex, paid tribute to his son in the form of a message to Alex's mom, Debbie, who died a decade earlier.
"Debbie, I never thought 10 years after I lost you, I would lose our son Alex sending him to high school. Please take care of him. I love you, Max," Alex Schacter wrote on his Twitter account.
Lori Alhadeff, whose 14-year-old daughter Alyssa died in the shooting, posted a tribute that showed a picture of a symbol that has come to memorialize her daughter: the number 8 that she used to wear on her soccer jersey, turned sideways to symbolize infinity.
ABC News' Shannon McLellan contributed to this report.