In the 1880s, a factory worker named Pierre Degeyter developed a melody for six verses and a chorus worth of words calling for working class men and women everywhere to fight against oppression. The song eventually became known as “The Internationale”—an enduring anthem of labor movements, socialist causes and revolutions. This remarkable film chronicles, through personal testimonies and incredible archival footage, the impact one simple yet moving song has had on the world since its introduction more than 100 years ago. A final testament to its power, the exuberant melody of “The Internationale” will haunt the mind long after the music has stopped playing.