Alfred Hitchcock, the fabled “master of suspense,” called Psycho a prank.

In fact, it was revolutionary. The film shocked audiences with its infamous 45-second “shower scene,” a heart-stopping sequence after which nothing would ever look the same.

Premiered on June 16, 1960, Psycho broke taboos and cinematic conventions. Hitchcock was coming off of North by Northwest, a romantic thriller with marquee idols Cary Grant and Eva Marie Saint, shot in the widescreen VistaVision format and marked by its astonishing action sequences. His follow-up was a black-and-white horror film in which he kills off the apparent lead character—Janet Leigh’s Marion Crane—not long into the film. Worse, she gets stabbed to death while taking a shower in the creepy Bates Motel, managed by Norman Bates, played by Anthony Perkins, whose performance as a cross-dressing, mother-obsessed, split-personality maniac would shadow every big-screen serial killer to come.

The sequence became a demarcation line in film history. “There were movies before the shower scene and movies after the shower scene,” says filmmaker Alexandre O. Philippe, whose 2017 documentary 78/52: Hitchcock’s Shower Scene explores Psycho and its signature scene in depth. (Its title alludes to the 78 camera set-ups and 52 edits made for the sequence).“It really was a game changer.”

And not only because the film boasted Hollywood’s first scene with a toilet.

Psycho became Hitchcock’s most successful film at the time—its box-office take, $32 million, was the second best of 1960, after Spartacus_._ But it was made despite much resistance. Paramount, the studio that had produced several of the director’s 1950s successes, refused to bankroll it. So Hitchcock financed its budget himself, against the advice of his own producers. The film also rattled the censors who executed Hollywood’s slackening Motion Picture Production Code, also known as the Hays Code, which was in effect from 1934 to 1968.

The censors balked at what they perceived as nudity in the shower sequence. Leigh wore moleskin patches to hide sensitive areas, as did her body double, pin-up model and future Playboy cover star Marli Renfro, who took over for more exposed moments. But there also was the opening scene, in which Leigh’s Marion wears only a bra and slip, sharing a hotel room with her divorced lover. The censors wanted that changed, too, but the savvy director tricked them. He sent back a copy of the shower scene that was unchanged, confusing the censors as to whether they had seen something or not. He also invited them to the set where he would reshoot the offending opening scene, but none of the censors showed up.

Much of the scene, which was storyboarded in consultation with the legendary designer Saul Bass (and took a week to film), was shot in extreme close-ups, with swift edits, so that the nudity and violence are implied—felt—but never actually seen. The shower set was constructed so that any of its walls could be removed, allowing the camera to get in close from every angle. And Hitchcock employed a fast-motion reverse shot to make it look like the blade actually pierced Marion’s abdomen.

The shrieking strings of composer Bernard Herrmann’s score ratchet up the tension.(It was a novel use of violins, which had usually been employed in film soundtracks to enhance a sense of romance or pathos.) Hitchcock at first resisted them, planning to use no soundtrack at all for the scene. To make the experience even more palpable, the sound of Marion’s flesh yielding to the knife was created by stabbing a casaba melon. Hitchcock had his crew audition multiple varieties of melon until they found the right kind.

Audiences have had six decades to adjust to such visual frenzy, but in 1960, the same year when wholesome, traditional films like Swiss Family Robinson and Please Don’t Eat the Daisies also dominated the box office, watching it might have induced panic.

“That was an era when you couldn’t obviously [hit] pause and go back,” says Philippe, “and look at it frame by frame. He was telling them [the censors] the truth. You imagined things that you didn’t really see. You don’t see violence. You don’t see nudity. You don’t see blood—it’s obviously chocolate syrup.”  As to how the director ultimately got the scene past the censors, Philippe ventures this theory: “He’s funny, he’s very chummy. He charmed them into it. I don’t have a better explanation. It’s kind of a magic trick.”

Not every great filmmaker knew how to pull off such a trick. Michael Powell, the venerated English director whose classics include The Red Shoes, wrecked his career with Peeping Tom, a 1960 thriller about a voyeuristic serial killer, which premiered a few months before Hitchcock’s film.

Psycho has had a pervasive influence on popular culture. Debuting on the cusp of the turbulent 1960s it helped to usher in a definitive cultural shift from the Eisenhower era. Its suggestion, noted by film critic Owen Gleiberman, that movie monsters were no longer fire-breathing Godzillas or space aliens but “lived inside the head of one man,” would soon enough be writ large in the real-life terror spawned by mass murderers like Charles Manson and Charles Whitman.

The film announced that “murder was now going to be an acceptable form of entertainment,” observes Bret Easton Ellis, author of the serial killer novel American Psycho, in 78/52_._ “There was violence in American film but nothing like Psycho—nothing that intimate, nothing that designed, nothing with that kind of remorseless.”

Its stylish, graphic intensity helped to inspire the homicidal thrillers of the Italian giallo movement and American drive-in slasher flicks alike, with artful filmmakers like Brian De Palma and John Carpenter crafting their own classic shockers in debt to Hitchcock’s example. There have been sequels and remakes (Gus Van Sant’s 1998 Psycho) and TV shows (“Bates Motel”), country ballads (the 1968 song “Psycho”) and new-wave hits (Talking Heads’ “Psycho Killer,” with singer David Byrne as a hopped-up version of Norman Bates). References to the film pop up everywhere, from “Saturday Night Live” to “The Simpsons.” Likewise, Herrmann’s threatening music, which has been recorded by the Los Angeles Philharmonic and emulated by John Williams for Jaws.

“It opened the Pandora’s box,” says Philippe, who credits Psycho as an artistic advance, yet an uneasy one. “It unleashed a whole wave of slasher movies and movies that were not as thoughtful or interesting—and cinematic violence against women. Especially naked women. Especially naked women in private spaces.”

But, he added, “its legacy in terms of the language of cinema is pretty extraordinary.”