March for Our Lives Students Lead Rally to Say ... Never Again!!!

3/24/2018 7:17 AM PDT

March for Our Lives: Students Rally to End Gun Violence, Many Celebs Join the Fight

Hundreds of thousands of kids and adults swarmed Washington D.C., demanding gun control in the wake of the Parkland massacre ... and Emma Gonzalez just closed it off by standing silent on stage for 6 minutes and 20 seconds -- the time it took the Florida shooter to kill 17 people at her school.

Parkland, FL students from Marjory Stoneman Douglas High School are leading the charge at the March for Our Lives rally, and they're being joined by an estimated half-a-mil others in D.C. as well as millions more in rallies across the country ... sending a message to ban assault rifles along with other sensible gun control measures.

Event organizers got a permit for 500,000 people for the D.C. rally, but the crowd size was reportedly closer to a whopping 800,000.

Some big musical acts -- including Miley Cyrus, Common, Demi Lovato, Lin-Manuel Miranda, Ariana Grande and Jennifer Hudson -- will perform at the D.C. rally, but only students will deliver messages.  We're told all of the students have some connection to gun violence.

The high schoolers will also perform their original song "Shine," written in the wake of the Parkland tragedy.

Paul McCartney showed up this morning to the march in N.Y.C. wearing an anti-gun t-shirt not far from where John Lennon was shot in 1980. 

In L.A. ... celebs like Amy Schumer, Olivia Wilde, Charlie Puth and Connie Britton will join in the downtown protest. All in all, there are 833 marches planned worldwide Saturday ... from the U.S. to  the UK, from India to Japan.

March on.