In this file photo taken April 12, 1963 Rev. Ralph Abernathy, left, and Rev. Martin Luther King Jr. lead a column of demonstrators as they attempt to march on Birmingham, Ala., City Hall. Arrested for leading a march against racial segregation in 1963, King Jr. spent days in solitary confinement writing his “Letter From Birmingham Jail,” which was smuggled out and stirred the world by explaining why Black people couldn't keep waiting for fair treatment. (AP Photo/Horace Cort)