1930s: Schools and most other public facilities across the South are segregated by race.

1956: The University of Alabama expels its first black student in defiance of a federal court order; Southern congressmen issue a manifesto pledging to use "all lawful means" to defy desegregation.

Today: Schools and public facilities are open to all regardless of race, but economic inequality is still seen by some as a barrier to full integration.

1930s: The first "talkie" was produced in 1928; a few years later all films have sound. Elaborately staged musicals become one of the movie industry's most popular genres.

1956: As a result of the country's rising prosperity following World War II, television is introduced to many homes, providing cheap, nearly endless entertainment. Movie attendance falls by millions, and many theaters close. The industry fights back by developing thousands of drive-in movie theaters.

Today: New forms of...