Santiago Mayer, executive director of Voters of Tomorrow, shed light on Generation Z's perspective at the Los Angeles rally.

"We have grown up in a world where we all jump when a balloon pops. In a world where we have to scan every single exit and the movements of our classmates at school," he said.

"We don't live like this because we like it … we live like this because every single day the people in power make the conscious decision to put the NRA's money over our lives," Mayer said. "It's incredibly frustrating to keep talking about this, because every time that we try and do something, the other side just throws their hands up in the air and gives us 'thoughts and prayers.'"

Meyer said that "Generation Z is done with the games, done with the 'thoughts and prayers.'"

"We must take action now," he said. "We must ban assault rifles and high-capacity magazines. We must invest in school counselors and social services. We must raise the minimum age to buy a gun to 21."

Lawmakers, he said, "can vote for common sense gun legislation, or young people will vote them out."

At the March For Our Lives rally in Los Angeles, one woman held a sign reading: "Send the guns to Ukraine."

Dr. Jeffrey Birnbaum, a pediatric emergency medicine doctor in LA and a Parkland, Florida, native, explained the severity of semi-automatic rifle injuries.

He recalled his first experience treating patients shot by semi-automatic rifles, saying "the images of their injuries will be forever burned into my mind."

"I vividly remember thinking that no one should be able to inflict these types of injuries on a fellow human being," Birnbaum told the crowd.

A survivor of the 2014 mass shooting at the University of California Santa Barbara also shared her experience at the LA rally. She said after the shooting, her mother begged her to drop out of college, terrified for her safety.

Last month's Uvalde, Texas, shooting came one day after the anniversary of the UCSB massacre. She said she doesn't want any other generation to endure this grief.

"I know that we are exhausted -- but we must continue showing up … because I can't take it anymore," she said.

Buffalo, New York, residents held a March For Our Lives rally on Saturday, weeks after a mass shooting that killed 10 shook their community.

Another rally was in Parkland, Florida, home to the 2018 school shooting that killed 17.

Americans in cities across the nation, from New York to Chicago, also joined in, taking to the streets and making their voices heard.

"We need fewer guns in schools -- not more of them!" Randi Weinstein, president of the American Federation of Teachers, said in a passionate speech in Washington, D.C.

"Teachers want to be teaching!" she said. "As we head back to school this fall, please arm us with resources -- with books, with school counselors. Not with bulletproof vests."

Weinstein also addressed critical race theory, noting, "If we have the judgment to shoot a bad guy, why don't we have the judgment to plan our lessons?"

Washington, D.C., Mayor Muriel Bowser told D.C. protesters she's frustrated because "we have been here before."

"We're not asking for a lot. We're asking to drop off our children at school without having to worry that someone will bring an AR-15 into their classroom. We are asking to go to the grocery store without worrying that someone will be shot dead by a gunman who is filled with hate. We are asking to let our children go to the playground without worrying that a car will drive by, firing a high-capacity magazine," the mayor said. "We're done asking. We're demanding change and we're demanding change now."

She urged Americans "who share our values to let their senators know that they neither need to make change now-- or get out of our way."