On April 16, 1902, Tally's Theatre opened its doors in Los Angeles, the first theatre to exclusively feature motion pictures. In 1952, a total of 1753 daily newspapers across the United States featured full or half page ads announcing the 50th anniversary of motion pictures. Two hundred and fifty Hollywood stars visited communities to promote the event (https://news.google.com/newspapers?nid=348&dat=19511004&id=hwoFAAAAIBAJ&sjid=fjEDAAAAIBAJ&pg=6753,230803&hl=en).
A spokesman for the event explained: "The purpose of the celebration is to focus unique position the motion picture industry has won in the last 50 years as the centre of each community's entertainment and to call attention to the superior quality of pictures to be released in the coming year." A contest was held at participating theatres, searching for "the typical American family", with the grand prize of a trip to Hollywood.
The same year, the U.S. Post Office issued a stamp to mark the anniversary, focussing on the unique role that motion pictures played in the lives of American troops. Far from home and immersed in battle, motion pictures were a welcome diversion for war weary soldiers (https://www.youtube.com/watch?v=Bdufvv_zevE).
President Truman greets Hollywood stars on the 50th Anniversary of Motion Pictures circa 1952 courtesy http://www.gettyimages.ca/pictures/washington-dc-president-truman-greets-motion-picture-news-photo-514704472.