Atlantic City Boardwalk, August 1964. Photograph by George Ballis. The Reverend Dr. Martin Luther King, Jr. addresses the Mississippi Freedom Democratic Party rally in front of the convention center. Behind him are images of James Chaney, Andrew Goodman, and Michael Schwerner, civil rights workers slain in Mississippi. © 1976, George Ballis / Photograph provided by TakeStock.

Deputies Approach Boy, Selma, Alabama, 1964. Photograph by Matt Herron. Sheriff's deputies coming to arrest a young boy holding a sign at a SNCC voter registration demonstration in front of the Dallas County courthouse. © 1976, Matt Herron / Photograph provided by TakeStock.

James Chaney Funeral, Mississippi, August 1964. Photograph by Matt Herron. Fannie Lee Chaney, mother of James Chaney, gives a funeral oration in the burned ruins of the Mt. Zion United Methodist Church. The three murdered civil rights workers were investigating this fire the night they were arrested. © 1976, Matt Herron / Photograph provided by TakeStock.

Civil Rights Workers Used Non-violent Demonstrations to Support Black Citizens Trying to Register, 1964. Photograph by Ted Polumbaum. Just 2 percent of eligible Black voters in Leflore County, Mississippi were registered in 1964, compared to 95 percent of eligible white voters. Ted Polumbaum/Newseum collection.