Fannie Lou Hamer, an activist who spent her career encouraging African-Americans to register to vote and to fight racial segregation, died of cancer in Mound Bayou, Mississippi, on March 14, 1977.
Hamer was born on Oct. 6, 1917, in Montgomery County, Mississippi, and was the youngest of 20 children. Her parents were sharecroppers in the Mississippi Delta area. At the age of 12, she dropped out of school and helped her family on a plantation where they worked full time. 
In the summer of 1962, Hamer registered herself to vote and joined a group of civil rights activists to travel to a county courthouse in Indianola to encourage others to vote. The act led to her getting fired from her job, but it only gave her the freedom to make the fight for voting rights her commitment for the rest of her life. 
Hamer went on to help found the Mississippi Freedom Democratic Party in 1964. She ran for Congress in Mississippi but did not win a seat. She also helped established the National Women's Political Caucus in 1971. Even after she was diagnosed with cancer in 1976, she continued to advocate for civil rights until her death in 1977. 
Listen to the audio below of Fannie Lou Hamer's famous speech at the Democratic National Convention on August 22, 1964.

 (Photo by John Dominis/The LIFE Picture Collection via Getty Images)