1939: With the onset of World War II, African Americans call for the desegregation of the U.S. military. While blacks are allowed to serve, they are only allowed to serve in non-combat and support roles. Some gains are made during the war; for example, although it is very controversial, black pilots train at Tuskegee University to fight in the conflict.

Today: The U.S. military has been entirely desegregated since 1948.

1949: Films such as Intruder in the Dust and Home of the Brave depict African Americans in supporting roles and as caricatures.

Today: African Americans, such as Denzel Washington, star in mainstream box office hits and deliver Academy Award-winning performances.

1950s: In the historic Brown v. Board of Education case, the Supreme Court rules that racial segregation in education is unconstitutional. Opposition to the ruling is huge, and organizations such as the White Citizens Council...