In this June 7, 1966 file photo, Mississippi Highway Patrolmen grapple with black marchers accompanying the Rev. Martin Luther King on a march along U.S. 51 south of Hernando, Miss. Thousands joined a march across Mississippi, started by James Meredith, to challenge a system that condoned violence against black people and suppressed their rights – issues still reverberating in national debates about police violence 50 years later. (Photo by AP Photo)
