The Selma to Montgomery march, also known as "Bloody Sunday," was a series of three protest marches that took place in 1965 from Selma, Alabama, to the state capital of Montgomery. The marches were organized by civil rights activists to demand voting rights for African Americans, who were being systematically disenfranchised in the South.

The first march took place on March 7, 1965, and was led by civil rights leaders including John Lewis, Hosea Williams, and Amelia Boynton. As the marchers crossed the Edmund Pettus Bridge, they were met by state troopers and local police who brutally attacked them with clubs, whips, and tear gas. The violence was broadcast on national television and shocked the nation, leading to a wave of public outrage.

Following the violent crackdown on the first march, a second march was attempted two days later but was stopped by a court order. Finally, on March 21, under federal protection, civil rights leaders successfully led a third march from Selma to Montgomery, with an estimated 25,000 people participating.

The Selma to Montgomery march and the events surrounding it played a pivotal role in the passage of the Voting Rights Act of 1965, which prohibited racial discrimination in voting and was a landmark achievement of the civil rights movement. The courage and perseverance of the marchers brought national attention to the ongoing struggles for racial equality and justice in America.