In the aftermath of the devastating mass shooting at Stoneman Douglas High School, youth activists worldwide are demonstrating today to demand an end to gun violence in our schools and communities.

Since the February shooting that claimed the lives of 17 students and faculty, survivors from the Parkland, Florida, school have galvanized a nationwide movement calling for gun reform. These students, including out activist Emma González, are leading the charge at the cornerstone March For Our Lives rally in Washington, D.C.

An estimated 500,000 protesters flooded Pennsylvania Avenue stretching from the main stage near the Capitol building to the White House.

As the final speaker at the D.C. event, González listed some of the activities her slain friends and classmates would never again get to do. She then let tears stream down her face during a prolonged moment of silence that marked the six minutes and 20 seconds it took for the Stoneman Douglas shooter to complete his reign of terror.

"Fight for your lives before it’s someone else’s job," she told the crowd.

González, who first made headlines with her moving call-to-action at a gun control rally after the shooting, is openly bisexual and the president of her school’s GSA.

The 18-year-old student activist was among the Parkland survivors who recently appeared on MSNBC's The Rachel Maddow Show. "We know that the politicians are going to say 'thoughts and prayers,' and that’s not what we want to happen this time around," she told Maddow. "We want this to stop—it’s time to break the pattern."

MTV, in partnership with NAACP Youth and College Division and local youth organizations, provided 17 buses to transport young people to the D.C. march from communities around the country affected by gun violence. The 17 buses represent the lives lost in the Parkland shooting and the more than 17 young lives lost to gun violence every day.

Celebrities such as Jennifer Lopez, Lady Gaga, Jimmy Fallon, The Roots, Yara Shahidi, Nick Cannon, Carmelo Anthony, Pusha T, Halsey, and Chloe x Halle have joined forces with MTV and NAACP to offer public support and encouragement to those participating in the D.C. march.

“Once again young people are at the forefront of driving change,” said MTV president Chris McCarthy in a statement, “and MTV is proud to amplify this youth-led activism.”

MTV and all Viacom networks, including Logo, went dark March 14 for 17 minutes in tandem with the National School Walkout to honor the 17 lives lost in the Parkland shooting and other young victims of gun violence. MTV used the opportunity to celebrate 17 young people leading the fight against gun violence across the country and is currently creating a documentary special about the crusade.

For more information visit enough.mtv.com.

Lin-Manuel Miranda, Ben Platt, Ariana Grande, Jennifer Hudson, Miley Cyrus, Demi Lovato, Common, Andra Day, and Vic Mensa are among those who performed at the March For Our Lives rally in D.C.

Watch González's speech at the 2:37 mark below.