Fifty years ago on Sunday, September 15, 1963, a bomb exploded at 16th Street Baptist Church in Birmingham, Alabama. The blast killed four little girls: Addie Mae Collins (14), Carole Robertson (14), Cynthia Wesley (14), and Denise McNair (11). Here are nine things you should know about the bombing.

1. The church, originally known as the First Colored Baptist Church of Birmingham, was founded in 1873. This was just 10 years after Lincoln’s Emancipation Proclamation and two years after the founding of the city of Birmingham. The original church on 16th Street was demolished in 1908. The city condemned the building because of structural inadequacies, but church members believe that city leaders considered the church, with its soaring steeple, to be too grand for an African American congregation.

2. Sixteenth Street Baptist Church was the largest and most elite black church in Birmingham. African Americans in the South were basically forbidden from assembling anywhere but inside a church, so the church also functioned as a civic hall. Many members of 16th Street held teaching and professional jobs. Fear that members would lose their jobs initially made church leaders hesitant about involving their congregation in the burgeoning civil rights movement, though the church eventually became the rallying point for the movement in Birmingham.

3. September 15 was Youth Sunday, a tradition in Baptist churches in which young people lead the worship service. The boys wore dark pants and white shirts, and the girls wore white dresses. Carole Robertson wore her first pair of heels that day.

4. The Sunday School lesson for the morning was “A Love that Forgives.” The sermon (which was never preached) was to be based on Luke 23:34: “Then Jesus said, ‘Father, forgive them; for they know not what they do.’”

5. There were actually five girls in the ladies’ restroom in the church basement, primping before the service, when the bomb went off. Sarah Collins, the younger sister of Addie Mae, survived with serious injuries. Her eyes and face were full of glass. She lost one eye and underwent many reconstructive facial surgeries.

6. Eight-year-old Condoleezza Rice heard the explosion from two miles away at the Presbyterian church pastored by her father.

7. The stained-glass window of the Good Shepherd survived intact, except for the face of Jesus, which was blown out. One of the other shattered windows was replaced with a stained glass window of a black crucified Christ paid for with money donated by the people of Wales.

8. Four members of the Ku Klux Klan—Robert Chambliss, Thomas Blanton, Herman Frank Cash, and Bobby Frank Cherry—planted 19 sticks of dynamite under the church. No one was indicted for the murders until 1977, when Chambliss was convicted and sentenced to life in prison. Herman Cash died in 1994 before he was ever charged. Blanton was convicted in 2001 and Cherry in 2002. Both were sentenced to life in prison. Blanton is the only one of the four still living.

9. At the funeral for the girls, Martin Luther King Jr. offered these words of comfort:

And so my friends, they did not die in vain. God still has a way of wringing good out of evil. And history has proven over and over again that unmerited suffering is redemptive. The innocent blood of these little girls may well serve as a redemptive force that will bring new light to this dark city.

King’s words would prove true as the death of four little girls galvanized the sympathy of the nation and the world for the cause of the civil rights movement. Survivors of the blast would never fully recover from the trauma, but 50 years later, they work to forgive their enemies and honor the legacy of four little girls.

Further information:

While the World Watched by Carolyn Maull McKinstry (Tyndale House, 2011)

Four Little Girls, a documentary by Spike Lee (1997)