The line comes from Martin Luther King Jr.'s 'I Have a Dream' speech, delivered on 28 August 1963 at the March on Washington for Jobs and Freedom in Washington, D.C. It became one of the most quoted speeches in American history and a defining moment of the civil rights movement. Short clips of the phrase later spread through documentaries, school lessons and online video, where editors reuse it as shorthand for hope, ambition and a better future. Its familiarity is why a fraction of a second still carries so much meaning.