Alabama state troopers wear gas masks as tear gas is fired on marchers in 1965. Fifty years ago, about 600 people began a 50-mile march from Selma, Alabama, to the state capital of Montgomery so that they could protest discriminatory practices that prevented black people from voting. But as the marchers descended to the foot of the Edmund Pettus Bridge, state troopers used brutal force and tear gas to push them back. It is now known as "Bloody Sunday."
Sheriff's deputies in Selma prepare to confront marchers on "Bloody Sunday."
Singer Harry Belafonte, right, was among the activists at the Selma to Montgomery marches.