While McCartney did not mention his late friend, John Lennon, by name, his bandmate was shot in NYC in 1980 by gunman Mark David Chapman.
In Washington D.C., Miley Cyrus, Ariana Grande, Common, Lin-Manuel Miranda and Ben Platt were among the performers who took to the stage to pay tribute to the 17 lives lost in the deadly school shooting in Parkland, Florida last month, as well as people impacted by gun violence elsewhere.
Paul McCartney tried to imagine a world without gun violence - while standing just steps away from the spot where his former band mate John Lennon was murdered.
When asked if change could happen at the legislative level, McCartney, who wore a shirt that said "We Can End Gun Violence", told Carroll, "I'm like everyone, I don't know". Speaking to CNN he explained that having lost a good friend of his to gun violence, it was a very important issue to him.
The primary one took place in Washington DC, with sister rallies taking place across the country, and even further afield, with more taking place in London and Edinburgh.
McCartney, 75, was joined by his wife Nancy Shevell on Saturday during the March for Our Lives on Manhattan's Upper West Side when spoke off-camera to CNN's Jason Caroll.