Students across the nation and on Long Island marked the 19th anniversary of the Columbine High School massacre with a walkout.

Thirteen people were killed in the Columbine shooting. At 10 a.m. in each time zone, students at dozens of schools left class to take moments of silence honoring the victims at Columbine and other shootings.

Students at Roosevelt High School silently walked around the building Friday morning. Earlier in the day, the kids took part in a forum on guns and school safety.

A sophomore who lost her brother to gun violence says the gun laws need to be changed.

"Kids bringing guns to school is not okay,” said Essencia Bermudez. “You should be worrying about what college you are going to, instead of wondering what you're going to wear to a friend’s funeral.”

At Island Trees High School, hundreds of students lined up on the football field – many holding signs with messages like "Bullets are not a school supply" and "This is not a drill."

In Manhattan, a die-in was held in Washington Square Park. The new chancellor of city schools had urged students not to leave class, but hundreds took off for the event.

At Marjory Stoneman Douglas High School, where 17 people were killed in February, students left class at 10 a.m., many wearing orange in honor of their fallen classmates and staff.