Emma Gonzalez, a leading and powerful voice in the movement spawned by the mass shooting at her Florida high school last month, brought hundreds of thousands of passionate protesters at the March for Our Lives rally in the nation's capital to a complete silence Saturday afternoon.

The 18-year-old student activist, who survived the shooting that claimed 17 lives at Marjory Stoneman Douglas High School, addressed the crowd by first reading the names of the students and educators who were killed in the Feb. 14 massacre.

Marjory Stoneman Douglas student Emma Gonzalez weeps as she speaks to the crowd that gathers in Washington D.C. for the March For Our Live rally in the wake of the shooting at Marjory Stonemason Douglas High School in Parkland.(Mike Stocker/South Florida Sun-Sentinel/Polaris) Marjory Stoneman Douglas student Emma Gonzalez weeps as she speaks to the crowd that gathers in Washington D.C. for the March For Our Live rally in the wake of the shooting at Marjory Stonemason Douglas High School in Parkland.

And then, for more than 4 minutes, Gonzalez -- tears streaming down her cheeks -- went silent and stone-faced.

The protesters went somber at first, before breaking into the powerful silence with chants of "Never Again!" "Never Again!"

Parkland, Florida school shooting survivor Emma Gonzalez is pictured on a sign during a March for Our Lives demonstration demanding gun control in Seattle, Washington, March 24, 2018.(Jason Redmond/Reuters) Parkland, Florida school shooting survivor Emma Gonzalez is pictured on a sign during a March for Our Lives demonstration demanding gun control in Seattle, Washington, March 24, 2018.

Gonzalez's pause represented the time it took the alleged shooter, Nikolas Cruz, to carry out the shooting.

A timer went off, breaking Gonzalez's silence.

"Since the time that I came out here it has been 6 minutes and 20 seconds," she said.

"The shooter has ceased shooting and will soon abandon his rifle, blend in with the students as they escape and walk free before arrest," she said, referring to Cruz. "Fight for your lives before it's someone else's job."

The March for Our Lives demonstration drew not only thousands of protesters to Washington, D.C., but also to rallies in cities across the United States and around the world. The organizers called on politicians to enact gun reform in the wake of mass shootings in schools and elsewhere.

Tears roll down the face of Marjory Stoneman Douglas High School student Emma Gonzalez as she observes 6 minutes and 20 seconds of silence while addressing the March for Our Lives rally, March 24, 2018 in Washington, D.C.(Chip Somodevilla/Getty Images) Tears roll down the face of Marjory Stoneman Douglas High School student Emma Gonzalez as she observes 6 minutes and 20 seconds of silence while addressing the March for Our Lives rally, March 24, 2018 in Washington, D.C.

Cruz allegedly walked into his former high school, killing the 17 victims and injuring several others. He was arrested after the shooting, and has since pleaded not guilty.

Gonzalez was one of the final speakers at the Washington, D.C., rally. Before her silent gesture, she seemingly spoke directly to victims of gun violence, especially those who survived the shooting at her school.

"Everyone who was there understands. Everyone who has been touched by the cold grip of gun violence understands," she said. "For us, long tearful, chaotic hours spent in the scorching afternoon sun were spent not knowing.

"No one understands the extent of what happened," she continued. "No one could believe there were bodies in that building waiting to be identified for over a day."

She said her friends and classmates would never do the mundane things they did before the shooting, or would never realize their dreams.

"My friend Carmen would never complain to me about piano practice," she said. "Aaron Fies would never ... Joaquin Oliver would never ... ," naming each of the 17 victims.