On August 28, 1963 the Rev. Martin Luther King, Jr. gave a speech on the steps of the Lincoln Memorial in Washington D.C. This oration is now knowing as the “I have a dream” speech. You may know this part “I have a dream that my four little children will one day live in a nation where they will not be judged by the color of their skin but by the content of their character.”
You can read and listen to the entire speech at American Rhetoric.
You can read background and analysis at Wikipedia’s “I Have a Dream” entry.