You’d think one of television’s longest-running series would have gotten a chance to go out on its own terms — but Gunsmoke’s cancellation in 1975 robbed its cast, crew, creatives, and fans of any sort of closure.

“We didn’t do a final, wrap-up show,” star James Arness, the actor behind Marshal Matt Dillon, told the Associated Press in 2002. “We finished the 20th year, we all expected to go on for another season, or two or three. The [network] never told anybody they were thinking of canceling.”