Gene Roddenberry pitched his show to executives at Desilu (makers of I Love Lucy) and NBC as a “Wagon Train to the Stars”-type, referring to the long-running popular television show about the early settlers in the U.S. A mix of action-adventure with sci-fi “with strong central lead characters plus other continuing regulars.” NBC executives were excited by one of the stories in Roddenberry’s outline, of a man displayed in a cage, like an animal at the zoo, and then offered a mate. They ordered a pilot, tentatively titled The Cage.

On this day, December 12, in 1964, the first pilot episode of Star Trek, one of the most celebrated and influential shows in television history, began shooting.

Roddenberry worked hard at writing and refining the script – perhaps a little too hard, as the NBC executives called the finished pilot “too cerebral,” “too intellectual,” and “too slow” with “not enough action.” But in an unusual move, they decided to give it another try, creating yet another pilot. To make up for the lack of a 16th episode in the season, The Cage was re-written as a two-parter and renamed “Menagerie.” All but a handful of the footage was used.