Reviewed sites by Neil Hollands in "Library Journal" (August 2011).
During the 1930's actors Orson Welles and John Houseman presented a radio show, "The Mercury Theatre on the Air." This show is remembered most for its October 30, 1938 broadcast of the "War of the Worlds" by H.G. Wells. Although listeners were cautioned that this was only a story, panic ensued across the country as people thought it was a real news broadcast and that the earth was being invaded by martians.
This timeline, developed by Dr. Beshero-Bondar, may be helpful if you are doing research on "The Watchmen."