An extraordinary student mobilization in the form of March for Our Lives brought hundreds of thousands to the streets of U.S. cities Saturday to demand tougher gun laws, in a muscular display of political determination less than six weeks after the Parkland school massacre.

At many of the March for Our Lives events across the United States, speakers reminded the hundreds of thousands of people in attendance that there was an important way they could push for gun reform: register to vote and go to the polls. 

According to many of the student speakers at the Washington rally, voting is the only way to pressure politicians to propose legislation that would meet the movement’s demands, which include universal background checks and bans on assault weapons and high-capacity ammunition magazines.

Teenage students who emerged as national figures in the aftermath of the Feb. 14 shooting flew to Washington to address the largest March for Our Lives rally, while thousands marched in Parkland, Boca Raton and cities around the globe.

There were protests in Boston, New York, Chicago, Houston, Minneapolis, Los Angeles and dozens of other cities. Thousands marched in Union Park west of downtown Chicago, holding signs that said “Never again” and “I stand with the students.” Protests were held around the world, with dozens in Europe and a scattering of others elsewhere.

Emma Gonzalez, a senior at Marjory Stoneman Douglas High School in Parkland, has emerged as one of the most prominent faces among the student activists who have mobilized against gun violence after a shooting at their school last month that left 17 dead. She stood on stage at the March for Our Lives for 6 minutes and 20 seconds, describing the effects of gun violence in emotional detail and reciting the names of classmates who had been killed.

“Six minutes and about 20 seconds,” she said. “In a little over 6 minutes, 17 of our friends were taken from us, 15 were injured and everyone in the Douglas community was forever altered.”

“Everyone who was there understands. Everyone who has been touched by the cold grip of gun violence understands. For us, long, tearful, chaotic hours in the scorching afternoon sun were spent not knowing. No one understood the extent of what had happened.”

It only took 6 minutes and 20 seconds, Gonzalez said, for a gunman and an AR-15 to extinguish the lives of the 17 students and faculty. She repeated the names of each of the victims and the things they would never do again.

Then, she stopped speaking. Silence gripped Gonzalez as tears rolled down her cheeks, and the crowd broke through with chants. But mostly, silence.

“Never again,” many in the crowd of 500,000 chanted in response. After 4 minutes and 25 seconds, a timer went off. Gonzalez said, “since the time when I came out here, it has been six minutes and twenty seconds.

The shooter has ceased shooting and will soon abandon his rifle, blend in with the students as they escape, and walk free for an hour before arrest,” she said. “Fight for your lives before it’s someone else’s job.” And then she left the stage.