March for Our Lives The nation’s capital has been preparing for weeks. Today, the voices will rise

WASHINGTON, DC - MARCH 24: People gather early in front of the stage before the start of the March for Our Lives rally on Saturday, March 24, 2018, in Washington, D.C. (Photo by Salwan Georges/The Washington Post)

Students, teachers, parents and survivors of mass shootings streamed into Washington Saturday for the March for Our Lives, a demonstration against gun violence that could draw hundreds of thousands of protesters to the nation’s capital.

The march is part of a surge of political activism that has transformed America’s entrenched debate over gun violence. It was organized by students who survived the mass shooting last month at Marjory Stoneman Douglas High School in Parkland, Fla., who hope to succeed where many adults have failed: By forcing Congress to pass a comprehensive gun-control bill that will improve school safety.

Hundreds of sister protests are taking place in cities across the U.S., including Philadelphia, New York, Chicago and Los Angeles. The main demonstration in Washington is scheduled to run from noon to 3 p.m. on Pennsylvania Avenue.

Many were crowding into downtown D.C. to stake out places at what promised to be less a march than a standing-room-only rally, with 20 speakers — all of them under 18 years old — and performances by celebrities including Ariana Grande, Common, Miley Cyrus, Jennifer Hudson, Vic Mensa, Lin-Manuel Miranda and Ben Platt.

Callie Stone, 18, was walking down Pennsylvania Avenue wearing a “Nasty Woman” denim jacket. With her was her mother, whom she had told her mother the previous day she wasn’t sure she wanted to raise children in a world where students fear going to school.

“But I said, ‘Look at you, at your generation — you all are bringing us hope,’” said her mother, Kelly Stone, 54.

Kelly Stone was in middle school in Canada in 1975 when a gunman killed two people and himself at Brampton Centennial Secondary School, which she went on to attend. The event has cast a long shadow over her life and that of her daughter, she said.

Nearly 200 have died in school shootings since the 1999 massacre at Columbine High School in Colorado, which left 13 dead and inaugurated a relentless, two-decade stretch of campus gun violence. During that period, more than 187,000 students attending at least 193 primary or secondary schools have experienced a shooting on campus during school hours, according to a Washington Post analysis.

Just five days ago, 16-year-old Jaelynn Willey was fatally shot at Great Mills High School in southern Maryland by a 17-year-old former boyfriend, who died as well. One other boy was injured in the gunfire.

For the roughly 100 students, alumni and parents from Great Mills High emerged from the escalator at the L’Enfant Plaza Metro station, the march had a raw immediacy.

“We are!” Emerson Schaeffer, 20, shouted into a megaphone.

“Great Mills!” cheered the crowd, decked out in their school colors, forest green and gold.

Willey was taken off life support two days ago. Schaeffer said he and friends had been thinking about attending the march even before the shooting.

“Then this happened,” he said, “and we said ‘Yep, we’re going.’”

Authorities in the nation’s capital said they were taking extra security precautions, in part because many of the protesters are expected to be teenagers.

The Department of Homeland Security, working with D.C. police and the mayor’s office, has set up a system to notify demonstrators of warnings or detours. (Text “March 24” to 888-777 to sign up.) Those entering the main march area have to pass through security check points.

The March for Our Lives is today. Here’s what you need to know.

Medical tents staffed by volunteers line the march route, doubling as gathering points where people can find each other if accidentally separated. Water is being made available to protesters and food trucks would be nearby, organizers said.

“As the young men and women from Parkland, Florida, have been preparing for Saturday’s event, the District has been preparing to keep them safe here in Washington,” Mayor Muriel E. Bowser (D) said this week.

Bowser and other city officials held a pre-march “Rally for D.C. Lives” at Folger Park Saturday morning. Among the hundreds pouring into the park ahead of time were three students at National Collegiate Prep High School a charter school in Southeast Washington who lamented that gun violence in the poorest neighborhoods of the nation’s capital don’t command the same national publicity as that in Florida.

“As soon as stuff happened in Florida, everyone wanted to do something, but every week someone gets shot in D.C.,” said Nevaeh Williams, 16-year-old sophomore who lives in Anacostia. Her cousin was shot four years ago, and she stopped taking the train to school in eight grade.

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“My father has to pick me up and take me to school,” she said, “because he doesn’t think it’s safe for me.”

Their classmate Zoruan Harris, the quarterback for the football team, was fatally shot in 2016.

“When it happens in a school in a nice neighborhood, it’s shown nationwide but we don’t get that attention,” said Danielle Perkins, a 16-year-old junior whose step brother and friend’s older brother were shot in recent months.

Lamont Odoms, a 17-year-old junior, said he was tired of fearing for his live during his 30-minute walk to school.

“We are the ones most affected. We are tired of having silent voices,” he said.

Survivors of other mass shootings are also expected to attend.

Brandon Wolf, a survivor of the 2016 mass shooting at Pulse nightclub in Orlando, said he will attend the march as a representative of the Pulse victims, including his friend Christopher “Drew” Leinonen and Leinonen’s boyfriend, Juan Guerrero.