GLEN MILLS, Pa. (AP/WTXF) - Students hoisted "Stand United" signs. They chanted ""Hey, hey, ho, ho - the NRA has got to go".
These scenes played out across the country as students put down their pencils and pens and walked out of class to protest gun violence. Activists hoped it would be the biggest demonstration of student activism yet in response to last month's massacre in Florida.
More than 3,000 walkouts were planned across the U.S. and around the world, organizers said. Students were urged to leave class at 10 a.m. local time for 17 minutes -- one minute for each victim in the Feb. 14 attack at Marjory Stoneman Douglas High School.
Hundreds of students poured out of Lower Merion High School Wednesday morning heard taking aim at the National Rifle Association and its policies.
"We do not add fire to fire," said senior Sarah McConnell. "And I do not feel safe in a school where I know that every teacher has a gun or that there is any gun in the school."
The high school demonstrators at Lower Merion--like similar walkouts across the nation--did not have to be seniors to feel empowered to speak up.
"If I feel as passionately as I do about this issue, I have to speak up," said freshman Ava Clifford. "I can't sit there and let other people do the work for me. It's time for me to use my voice."
School district officials asked Lower Merion police to keep an eye on the event and outsiders hoping to add their voices were kept away.
The walkout was followed by a voter registration drive inside the school. Many of the seniors at Lower Merion are or soon will be old enough to vote. Then, they'll have the chance to turn protest into policy.
Stoneman Douglas High senior David Hogg livestreamed the walkout at the tragedy-stricken school in Parkland, Florida, on his YouTube channel. Walking amid a mass of people making their way onto the football field, he criticized politicians for not taking more action to protect students.
He said the students could not be expected to remain in class when there was work to do to prevent gun violence.
"Every one of these individuals could have died that day. I could have died that day," he said.
From Florida to New York, students poured out of their schools, marching through the streets or gathering on campus to demonstrate.
Some schools applauded students for taking a stand or at least tolerated the walkouts, while others threatened discipline.
The coordinated walkout was organized by Empower, the youth wing of the Women's March, which brought thousands to Washington last year.
Although the group wanted students to shape protests on their own, it also offered them a list of demands for lawmakers, including a ban on assault weapons and mandatory background checks for all gun sales.
"Our elected officials must do more than tweet thoughts and prayers in response to this violence," the organization said on its website.
Other protests planned in coming weeks include the March for Our Lives rally for school safety, which organizers say is expected to draw hundreds of thousands to the nation's capital on March 24. Another round of school walkouts is planned for April 20, the 19th anniversary of the Columbine High shooting in Colorado.
Some students in Massachusetts said that after Wednesday's protest, they planned to rally outside the Springfield headquarters of the gun maker Smith & Wesson.
The walkouts drew support from companies including media conglomerate Viacom, which planned to pause programming on MTV, BET and all its other networks for 17 minutes during the walkouts.
Districts in Sayreville, New Jersey, and Maryland's Harford County drew criticism this week when they said students could face punishment for leaving class.
In suburban Atlanta, one of Georgia's largest school systems announced that students who participated might face unspecified consequences. Some vowed to walk out anyway.
"Change never happens without backlash," said Kara Litwin, a senior at Pope High School in Cobb County.
The possibility of being suspended "is overwhelming, and I understand that it's scary for a lot of students," said Lian Kleinman, a junior at Pope High. "For me personally, this is something I believe in. This is something I will go to the ends of the Earth for."
Other schools sought a middle ground, offering "teach-ins" or group discussions on gun violence.
Meanwhile, free speech advocates geared up for a battle. The American Civil Liberties Union issued advice for students who walk out, saying schools can't legally punish them more harshly because of the political nature of their message. In Pennsylvania, Wisconsin and Texas, some lawyers said they would provide free legal help to students who are punished.