Mahalia Jackson's dynamic voice has soothed the souls of millions of Americans and was a shining light in the civil rights movement in the 60's. Now the Robin Roberts' biopic on the legendary singer. Nightline co-anchor Juju Chang reports. | Nightline

Mahalia Jackson sings "How I Got Over" on August 28, 1963 at a march in Washington, D.C. Later at that march, as Martin Luther King, Jr. spoke, Jackson shouted from the crowd, “Tell them about the dream, Martin!” prompting his most famous speech: | Legacy Recordings