The explosion in the opening scene is the infamous 16th Street Baptist Church bombing, which occurred in Birmingham, Alabama on September 15, 1963. The 4 young girls killed in the bombing were Addie Mae Collins, Denise McNair, Carole Robertson, and Cynthia Wesley.
David Oyelowo's last scene to be filmed was the Nobel Peace Prize acceptance speech. He immediately broke down into tears after wrapping the scene, to enthusiastic applause from extras and crew.
Tim Roth grew up during the Civil Rights Era. He said he remembers George Wallace, thought of him as a "monster," and was "amazed at what was coming out of his mouth."
Congressman John Lewis served as a mentor and historical consultant to director Ava DuVernay. On one rare occasion when she invited him to the set to observe a scene at the Rutledge Baptist Church (his district) with David Oyelowo (as Martin Luther KIng), Lewis was reduced to tears after an impassioned rehearsal speech by Oyelowo. Lewis had been a personal friend of MLK, and so the sad memories flooded back to him.
The Martin Luther King Jr. estate had already licensed the film rights for his civil rights speeches to DreamWorks and Warner Brothers for a yet to be produced biopic. For this film, Ava DuVernay wrote new variations of those speeches.