(WASHINGTON) -- Sunday marks the 50 year anniversary of when four young girls were killed in the Birmingham church bombing. The girls, whom Martin Luther King Jr. called "martyrs" in the fight for racial equality, were posthumously awarded one of the country's highest civilian honors this week.
The girls, all black members of Birmingham's 16th Street Baptist Church, were killed in 1963 when a white supremacist planted a bomb in the church on a Sunday morning.
On Tuesday, the girls were awarded the Congressional Gold Medal, a rare honor that requires an act of both houses of Congress.
Addie Mae Collins, 14; Denise McNair, 11; Carole Robertson, 14; and Cynthia Wesley; 14, were killed Sept. 15, 1963, in the attack that struck the packed church on a Sunday morning. Twenty-two others were injured.
The bomb, composed of dynamite and a timer, was planted beneath the front steps of the church, outside a basement room in which 26 children attended a Sunday school sermon.
The blast sent a fireball into the air, blowing out a stained-glass window, sending shrapnel into the air and melting metal fixtures.
Police and fire officials searched the scene, first looking for bodies and then evidence. But at the time, few black residents of Birmingham, a hotbed of racial tension that had become so dangerous it was called "Bombingham," believed justice would be served.
At a memorial service for the girls, three days after the blast, Martin Luther King Jr., said, "These children — unoffending, innocent, and beautiful — were the victims of one of the most vicious and tragic crimes ever perpetrated against humanity."
Their deaths helped galvanize much of the country against segregation, and toward a trial of the suspects.
Witnesses reported seeing Robert Chambliss, an avowed white supremacist and member of the Ku Klux Klan.
Following a short trial, less than a month after the bombing, Chambliss was found guilty of possessing dynamite and received a $100 fine. He spent six months in jail.
In 1971, Alabama Attorney General William Baxley reopened the case. Using evidence in a sealed FBI file, prosecutors charged Chambliss with murder. In 1977, he was convicted and sentenced to life in prison, where he died in 1985.
In 2000, the federal government pressed charges against three other men: Herman Cash, Thomas Blanton and Bobby Cherry, all of whom, along with Chambliss, were accused of belonging to a KKK gang called Cahaba Boys.
Cash had died by then, but in 2002, Blanton and Cherry were tried for their roles in the church bombing and found guilty of murder.
Reverend Joseph Lowery, the former president of the Southern Christian Leadership Conference, said the perspective of time does not diminish the atrocity that took place on September 15th 1963. "It was a terrible terrible day, it's hard to imagine human beings planning some cruelty in their hearts to plant a bomb in Sunday school," Lowery said.
Lowery is in Alabama alongside Attorney General Eric Holder and former United States Secretary of State Condoleeza Rice commemorating the bombing.
The Congressional Medal of Honor has been bestowed on other heroes of the civil rights movement, including Martin Luther King Jr., Rosa Parks, and Jackie Robinson. Each medal is designed and minted specifically for its recipient.
Legislation to create the medal was co-sponsored Rep. Terri Sewell, D-Ala., and Rep. Spencer Bachus, R-Ala.
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