In May 1963, news photographer Charles Moore was on hand to document the Children’s Crusade, a civil rights protest. But the photographs he took that day did more than document an event; they helped change history.

His photograph of a trio of African-American teenagers being slammed against a building by a blast of water from a fire hose was especially powerful. The image of this brutal treatment turned Americans into witnesses at a time when hate and prejudice were on trial. It helped rally the civil rights movement and energized the public, making civil rights a national problem needing a national solution. And it paved the way for Congress to finally pass laws to give citizens equal rights regardless of the color of their skin.