The nationwide March for Our Lives movement steps off in cities throughout the country today. The young activists organizing the events have strong celebrity backing.
"Time for gun laws to change," posted Marvel star Chris Evans, appearing as Captain America next in Atlanta-filmed "Avengers: Infinity War" next month.
Alyssa Milano, who campaigned for Jon Ossoff during his unsuccessful bid to fill former U.S. Rep. Tom Price's sea t, has posted several items, including a link giving information on local marches.
Watch live coverage of marches in Atlanta and elsewhere today on WSBTV.com.
The main event, in Washington DC, has been put together by Marjory Stoneman Douglas High School students in response to the massacre at their school last month. Suspect Nikolas Cruz, 19, is accused of opening fire at the Parkland, Fla., school on Feb. 14, leaving 17 dead and many others injured.
MORE : Events in Georgia
George and Amal Clooney are among the prominent backers, announcing a $500,000 donation to help with logistics. Moved by their support, Oprah Winfrey matched the gift.
Locally, U.S. Rep. John Lewis will give keynote remarks .
Here's a look at some of the celebrity support behind today's demonstrations.