In the name of African American voting rights, 3,200 civil rights demonstrators in Alabama, led by Martin Luther King, Jr., begin a historic march from Selma to Montgomery, the state’s capital. Federalized Alabama National Guardsmen and FBI agents were on hand to provide safe passage for the march, which twice had been turned back by Alabama state police at Selma’s Edmund Pettus Bridge.

In 1965, King and his Southern Christian Leadership Conference (SCLC) decided to make the small town of Selma the focus of their drive to win voting rights for African Americans in the South. Alabama’s governor, George Wallace, was a vocal opponent of the African-American civil rights movement, and local authorities in Selma had consistently thwarted efforts by the Dallas County Voters League and the Student Nonviolent Coordinating Committee (SNCC) to register local blacks.

Although Governor Wallace promised to prevent it from going forward, on March 7 some 600 demonstrators, led by SCLC leader Hosea Williams and SNCC leader John Lewis, began the 54-mile march to the state capital. After crossing Edmund Pettus Bridge, they were met by Alabama state troopers and posse men who attacked them with nightsticks, tear gas and whips after they refused to turn back.

READ MORE: Civil Rights Movement Timeline

Several of the protesters were severely beaten, and others ran for their lives. The incident was captured on national television and outraged many Americans.

King, who was in Atlanta at the time, promised to return to Selma immediately and lead another attempt. On March 9, King led another marching attempt, but turned the marchers around when state troopers again blocked the road.

On March 21, U.S. Army troops and federalized Alabama National Guardsmen escorted the marchers across Edmund Pettus Bridge and down Highway 80. When the highway narrowed to two lanes, only 300 marchers were permitted, but thousands more rejoined the Alabama Freedom March as it came into Montgomery on March 25.

On the steps of the Alabama State Capitol, King addressed live television cameras and a crowd of 25,000, just a few hundred feet from the Dexter Avenue Baptist Church, where he got his start as a minister in 1954.

READ MORE: How Selma's 'Bloody Sunday' Became a Turning Point in the Civil Rights Movement