<P> Another change was the infusion of story lines based on actual events and medical developments that materialized during the Korean War . Considerable research was done by the producers, including interviews with actual MASH surgeons and personnel to develop story lines rooted in the war itself . Such early 1950s events as the McCarthy era, various sporting events, and the stardom of Marilyn Monroe were all incorporated into various episodes, a trend that continued until the end of the series . </P> <P> While the series remained popular through these changes, it eventually began to run out of creative steam . Korean War doctors regularly contacted producers with experiences that they thought might make for a good storyline, only to learn the idea had previously been used . Harry Morgan admitted that he felt "the cracks were starting to show" by season 9 (1980--1981). Alda wished to make season 10 (1981 - 1982) M * A * S * H's last, but was persuaded by CBS to produce a slightly shortened 11th season, coupled with a farewell movie finale, because CBS refused to let the show go away so easily . In the end, season 11 had 15 episodes (although six had been filmed during season 10 and held over) and a 2 - 1 / 2 hour movie, which was treated as five episodes and was filmed before the nine remaining episodes . The final episode ever produced was the penultimate episode "As Time Goes By". The series finale movie, titled "Goodbye, Farewell and Amen", became the most - watched television broadcast in history, tallying a total of 125 million viewers . </P> <P> The 4077th consisted of two separate sets . An outdoor set in the mountains near Malibu, California (Calabasas, Los Angeles County, California) was used for most exterior and tent scenes for every season . This was the same set used to shoot the movie . The indoor set, on a sound stage at Fox Studios in Century City, was used for the indoor scenes for the run of the series . Later, after the indoor set was renovated to permit many of the "outdoor" scenes to be filmed there, both sets were used for exterior shooting as script requirements dictated (e.g., night scenes were far easier to film on the sound stage, but scenes at the chopper pad required using the ranch). </P> <P> Just as the series was wrapping production, a brush fire destroyed most of the outdoor set on October 9, 1982 . The fire was written into the final episode as a forest fire caused by enemy incendiary bombs that forced the 4077th to bug out . </P>

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