Less than a week after the 50th anniversary of the signing of the 1964 Civil Rights Act, a civil rights leader marked another anniversary.

Monday morning, Congressman John Lewis (D-GA) tweeted “ 53 years ago today I was released from Parchman Penitentiary after being arrested in Jackson for using "white" restroom.”

That tweet contained Lewis’ Jackson Police Department mugshot. The photo went viral, receiving more than 20,000 retweets.

Lewis told The Atlanta Journal-Constitution that he sent the tweet to “educate and inform people who were not even born 53 years ago.”

And it did. When Twitter user @JaPharii757 asked “How long did they hold you?” Lewis replied “I was arrested on May 24, 1961 and I spent more than a month in jail before being released.”

That 1961 arrest wasn’t Lewis’ first. The now-Congressman was one of the Freedom Riders—a group of more than 400 students who rode buses across the South to challenge segregation and Jim Crow laws. As a student at Fisk University, Lewis was heavily involved in the Nashville Student Movement, where he organized sit-ins at segregated lunch counters. By the time he joined the 1961 CORE Freedom Ride, 19-year-old John Lewis had been arrested five times.

Lewis convinced his cohorts from Nashville to get involved in the Freedom Riders movement. He rode to Birmingham, Alabama with the group and was arrested Jackson, Mississippi. Lewis and many of the other Freedom Riders were sent to Mississippi's Parchman State Prison Farm.

During the height of the Civil Rights Movement, Lewis was named Chairman of the Student Nonviolent Coordinating Committee (SNCC). He was also the youngest speaker at the 1963 March on Washington.

Freedom Riders, the PBS documentary from American Experience, told the story of Lewis and the young activists who rode the buses in the South. It features testimony from the Riders themselves, state and federal government officials, and journalists who witnessed and covered the Rides.

You can view the documentary on PBS.org

Tags: American experience, Freedom Riders, Congressman John Lewis, Civil Rights Movement