1920: The first commercial radio broadcast takes place August 20, on station WWJ in Detroit.

1922: Network broadcasting begins when WJZ and WGY in New York broadcast the World Series.

1926: The Radio Corporation of America (RCA) begins the first national network which helps connect the entire nation.

1931: Kate Smith's own radio show airs.

1932: The Shadow, a radio drama, is first broadcast, and lasts until 1954. Other shows that aired this year include Buck Rogers, The Adventures of Charlie Chan, The Ed Sullivan Show, The Marx Brothers, and Tarzan.

1934: Let's Pretend is first broadcast, and lasts until 1954.

1952: Bishop Fulton J. Sheen moves to television from radio. His show, "Life is Worth Living," is the first religious television show in New York when there are very few television sets in the city.

1954: Bishop Fulton J. Sheen reaches 25 million people on television. In 1955, Sheen is broadcast across 170 stations in the United...