On June 20, 1975, Hollywood released a movie that would not only break records for years to come but, also, for better or worse, change the way the industry would forthwith release and market their product. The movie and its director created what is now widely known as the ‘opening weekend.’

Golden Globe winner Steven Spielberg was 29-year-old when he helmed Jaws, his brilliant adaptation of the Peter Benchley novel. Spielberg was known as Hollywood’s wunderkind, a young genius who had burst onto the scene armed with tons of ideas and youthful enthusiasm. He had directed short films, assorted episodes for televised series, and some TV films (Duel, a tremendous road-thriller made for television, is still considered a masterpiece). Jaws was only his second theatrical feature after Sugarland Express, which the studio deemed a flop.

It is a favorite pastime of film journalists to accuse Spielberg of ruining the organic slow-growing success of a film by word-of-mouth. They like to say that he was the very one who started the mad-dash and very expensive marketing strategies that the studios have adopted. Since Jaws, films have been expected to rake in three times their production cost during the first weekend in theaters – that is, if they want to just break even.

This thesis is a bit unfair to the director. Spielberg did not produce Jaws, after all. That job fell to the legendary duo of David Brown and Richard Zanuck. What the young director felt in his gut was that the movie would be hugely successful, as he told the HFPA: “I even predicted what the film would make – in a sealed envelope that I gave the president of the studio, Sid Sheinberg. But it went way beyond my expectations. Way beyond anybody’s.” May we dare ask what dollar figure had been scribbled on that piece of paper? “It’s a little embarrassing. I thought the film would make $31 million in this country.” After one week in theaters, Jaws had taken a whopping $140 million bite out of the US box office. To date, a film that cost $7 million has made $472 million worldwide.

It was certainly not an easy project. The shark, named Bruce after Spielberg’s lawyer, kept malfunctioning. The weather washed away shooting schedules. Nantucket Island was supposed to be the location for the fictional Amity Island described in the best-selling book but, after a storm, the crew moved to Martha’s Vineyard. There, the director’s buddies George Lucas and John Milius came to visit and check out the mechanical development of the shark. Lucas got his head stuck in Bruce’s mouth when Milius and Spielberg grabbed the controls and clamped the jaw shut. After prying Lucas loose, the three snuck out of the workshop, not sure if they had ruined the entire contraption.

Spielberg threatened to walk off the project three times over disputes on how to shoot the film. “I was ready to quit when I heard that some people at the studio were considering making the movie in a tank – with miniatures.” He wanted the ocean, the high seas, the realness of danger.

And got it. Except for one pivotal scene where Richard Dreyfuss’ character, Hooper, discovers the severed human head. Spielberg had shot the scene in a tank but hated the way it looked. Fortunately, his legendary editor, Verna Fields, offered up her backyard swimming pool to reshoot the scene. A gallon of milk, taken right there and then from Verna’s fridge, was poured into the pool. It worked. It made the water look more like the real ocean.

Surprises and raw improvisation kept happening daily. No one wrote the movie’s most famous line, “You’re gonna need a bigger boat,” uttered by Roy Scheider, who plays Brody. Scheider simply said it on the day of the actual shooting. Everyone loved it. So, it stayed in. Spielberg sort of appears twice, Hitchcockian style, but only on audio. He plays the island’s dispatcher. His voice can be heard over the radio, on the boat. He played amateur clarinet on the soundtrack because composer John Williams needed someone who was not a professional. Spielberg also lent his pets to the film. Police chief Brody’s dogs are played by the director’s cocker spaniels, Elmer and Zalman. To top it all off, the iconic movie poster was not even an original designed for the film. It was merely taken from the novel’s paperback cover.

So, what about the famous marketing strategy? Spielberg was very vocal while promoting the film and even told the HFPA how he really felt: it was all unnecessary overkill. “I’ll be drawn and quartered for saying this but a film like Jaws didn’t need as much promotion as it got. Most of it was accidental and automatic. I think that there should be a category for chutzpah. Jaws, which had so much pre-hype, it’s kind of like beating the dog to death to kill the fleas.”

The fact remains that the studio went above and beyond to create massive awareness, even telling the media during filming about all the armed guards that had been hired just to protect the secrecy of the shark. Maybe that was intended to kick up the sense of anxiety within the press. Truth is, we now know that Time magazine was able to swipe one of the first pictures. The Christian Science Monitor newspaper swiped the second picture. Bruce was already a star.

Spielberg has always maintained that “they really couldn’t have moved the picture an inch if there wasn’t an audience out there already pre-conditioned to wanting to see the movie. Promotion only pushes a little bit farther. Promotion only gives it some more thrust. It doesn’t make or break a film. It could break a film, but it really can’t make a film.” Some people might argue this specific point. But everyone can agree that Jaws was the film business’ first true mega-blockbuster, that it changed the industry, that it will continue to scare and excite generations of fans.