Crowds gathered in Lafayette Park across from the White House in Washington, D.C., on Friday before the National School Walkout protests began.

At schools across the country today, students are getting up from their desks and walking out when the clock strikes ten. They're participating in the National School Walkout, part of the movement that has taken hold among students to call for action to end gun violence.

Today marks 19 years since the shooting at Columbine High School in Littleton, Colo., in which two high school students shot and killed thirteen people.

It's also been a little more than two months since the shooting at Marjory Stoneman Douglas High School in Parkland, Fla.

The walkout begins at 10 a.m. in each time zone, and organizers said that over 2,600 walkouts were planned – at least one in each state.

In Washington, D.C. students gathered in front of the White House with signs.

And at 10 a.m., they began the walkabout with 19 minutes of silence, in remembrance of the Columbine massacre.

Then, with chants against the NRA, students began marching to the U.S. Capitol.

In Nashville, Tenn., students carried signs and marched to the city's Public Square, near that state's capitol.

At Butler High School in Matthews, N.C., a suburb of Charlotte, students gathered in the bleachers.

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