Martin Luther King knew well that what he was about to do could well pour oil over the simmering American conflict over civil rights. Just weeks before, a peaceful protest planned to go from Selma, Alabama to the state’s capitol in Montgomery was brutally broken up by police. Sympathy protests, evolving into riots, sprang up around the country, culminating in a student-led clash with police at the site of the Democratic National Convention. MLK also knew that he had an opportunity with his act to  bring the tensions down.

On this day, March 21, in 1965 Martin Luther King began a second march from Selma to Montgomery. He was joined by several religious leaders, including a rabbi and a nun, and the crowd of 25,000 had not only blacks, but also Asians and Latinos.

The march itself went without incident, owning to the heavy security surrounding it. The protesters reached the steps of the state capitol several days later, and a “Stars for Freedom” rally nearby had concerts by Peter Paul & Mary, Nina Simone, Sammy Davis Jr. and other. King’s march spurred the passage of the Voting Rights Act of 1965 that forbade the disenfranchising citizens “on account of race or color.” As King promised his followers, “We shall overcome.”