In this Sept. 15, 1963 photo, policeman stand guard outside the 16th Street Baptist Church in Birmingham, Ala., which was the scene of an explosion that killed four African American children. President Barack Obama signed an order Thursday, Jan. 12, 2017, designating an historic civil rights district in Birmingham as a national monument, placing several blocks of a city once rocked by racial violence on par with landmarks including the Grand Canyon. (AP Photo)