Though today, Jaws is one of the most financially successful, critically acclaimed, and influential American films of all time, when it was released 50 years ago today, on June 20, 1975, it was far from a sure thing.

Though the studio supported the film, there was some concern because it was embracing so many “firsts.” The shoot had gone vastly over-budget and dealt with grueling production delays, largely due to Steven Spielberg‘s decision to make it the first film to ever be shot on the actual open sea, instead of a studio backlot. It was also the first film to engage in a modern-day marketing frenzy, with producers hyping the film up on the talk show circuit months in advance, and TV ads running frequently across the nation in the week before the premiere: