Martin Luther King Jr. was assassinated on April 4, 1968. Half a century later, King remains one of the most vivid symbols of hope for racial unity in America. But that's not the way he was viewed in the last year of his life.

More on Martin Luther King Jr.'s final year

Exactly one year before his death, Martin Luther King Jr. made a controversial speech condemning the Vietnam War.

In the last months of his life, King struggled to organize a massive march on Washington against poverty. He planned to use civil disobedience to close the capital down.

In the spring of 1968, King led a disastrous demonstration of striking garbage workers in Memphis. When he was killed, King was trying to prove the power of non-violence.

For six years, the FBI conducted a relentless campaign to spy on and discredit King. See for yourself many of the once-secret documents in King's FBI file.