The March for Our Lives, a nationwide protest against gun violence, took place on March 24. Survivors at Marjory Stoneman Douglas High School in Parkland, Florida, organized the march after 17 people were fatally shot at their school last month.

In the video, a crowd chants “MSD strong” (for Marjory Stoneman Douglas High School) at the March for Our Lives rally in Washington, D.C.