Survivors of the deadly Valentine's Day shooting at Marjory Stoneman Douglas High School in Parkland, Fla. (along with numerous celebrities such as Oprah, George and Amal Clooney, Steven Spielberg, Chrissy Teigen and a handful of other celebrities) are leading some 500,000 high school students Saturday during the "March for our Lives" anti-gun protest in Washington, DC.

The march was organized to build on the momentum of last week's National School Walkout and put further pressure on lawmakers to ban assault weapons after shooter Nikolas Cruz killed 17 students and faculty with an AR-15.

Participants gathered on Pennsylvania Avenue near the US Capitol on Saturday morning ahead of the march, which was slated to begin at noon.