Guiding Light, the longest-running program in broadcast history, is going off the air after more than 70 years. The soap opera will air its last episode on September 18, concluding a run that began before television. It first aired on NBC radio on January 25, 1937, before moving to TV in June 1952. After airing more than 15,000 episodes, CBS executives decided to cancel the show because of declining ratings. Fans were upset when the network announced its plans earlier this year to pull the plug on Guiding Light, and many threatened to boycott CBS and the program’s sponsor, Procter & Gamble. For the two weeks following the last episode, Guiding Light’s time slot will be filled with reruns of The Price is Right.