A generation raised on gun violence sends a loud message to adults: Enough!!

In the most dramatic display of civic activism by American students in recent memory, tens of thousands walked out of their schools Wednesday and took part in somber, politically charged student walkout demonstrations marking the Feb. 14 shooting that killed 17 educators and students at Marjory Stoneman Douglas High School in Parkland, Fla.

Some events were solemn and at times silent remembrances of the lives lost, while at other demonstrations participants demanded stricter gun control measures and vowed repercussions for elected leaders who failed to heed the call.

Participants read the names of each victim; others stood in silence around sets of empty chairs. At Granada Hills Charter High School in Los Angeles, students lay down on a football fieldto spell out the walkout’s rallying cry: “Enough.”

Organizers hoped the nationwide walkout—which appeared to be orderly and peaceful, despite concerns about the potential for disruption—would be a powerful spark to a broader youth-led movement around stemming gun violence.

At Stoneman Douglas High, students gathered on the school football field for 17 minutes before moving to a nearby public park.