It only lasted minutes, but images of sheriff's deputies lobbing tear gas and beating civil rights marchers with batons and whips on March 7, 1965 energized the nation into fighting against segregation in the South.

50 years ago, Martin Luther King Jr.'s Southern Christian Leadership Conference began a series of marches from Selma, Alabama to the state capital of Montgomery as part of a push for black voting rights.

The first of the three marches became known as "Bloody Sunday." The second came days later as King led protesters on a march to the scene of the violence, but no further to avoid violating the judge's order. A third march — that came with federal backing — began on March 21 and made the 50-mile stretch from Selma to Montgomery. That year, Congress passed the Voting Rights Act, which gave African-Americans the right to vote.