The idea of ghost sightings has spooked viewers since cameras could function. An article from Encyclopedia.com offers, "From the very beginnings of photography and cinema, spiritualists and psychical researchers have hoped to be able to capture evidence of ghosts on film and thereby offer proof of the survival of the human spirit." In search of answers to our burning questions, people have pursued this authentication by delving into the spiritual realm and crossing over into the cinematic scape to portray these investigative endeavors. Whether they're seemingly real – like episodes of Ghost Adventures – or truly fictional occurrences, the potential existence of ghosts has always piqued our curiosity.

One particular example stands out from the rest as a landmark of horror cinema, and that is Poltergeist. With its creepy atmosphere, quotable one-liners, and dark production history, this film has a devoted fan following and a storied reputation for good reason. Two sequels followed the first film – Poltergeist II: The Other Side and Poltergeist III – as well as a 2015 retelling of the original. One of the best haunted house movies, the story follows the haunting and increasing misfortunes of the Freeling family after their young daughter, Carol Ann (Heather O'Rourke), contacts ghosts through their TV. The true backstory of this movie might shock you. Here's why Poltergeist stands above other ghost films.

Quotable and Visually Memorable Scenes

Heather O'Rourke in Poltergeist.
Metro-Goldwyn-Mayer

Poltergeist is regarded as a bit of a cult classic today. This is due in part to its quotable one-liners and visually stunning scenes that make use of traditional horror imagery set against the backdrop of suburban comfort. Whether you've seen the film or not, you've probably heard or seen this reference somewhere: a kid's small hands set against the static of an old TV set as she creepily turns to the camera and intones, "They're heeeere." The visual translation of the ghostly visitor, known as the Beast, quickly comes across as more of a malevolent force than just a friendly voice that adults can't seem to hear until it's too late. This film also played heavily with the idea of "going into the light," which Diane Freeling (JoBeth Williams) calls out to her daughter after she's sucked through the ether.

And who could forget the creepy clown thrown into the mix, falling into an already perfect recipe for a horror movie? Before the Freeling family flees their increasingly haunted home, a clown doll springs into action and grabs middle-child brother Robbie (Oliver Robbins), dragging him into the abyss under his bed. The jump scares in this scene alone, besides the action that ensues, are enough to creep out viewers of all ages. In the 2015 remake of the film, another clown doll – with a more well-worn look in the new millennium – made a long-awaited appearance in the first trailer to be released.

Related: Poltergeist Fans Celebrate 40 Years of Suburban Horror

Real-Life Inspiration

The family in Poltergeist.
MGM/UA Entertainment Co.

The story behind Poltergeist was actually inspired by a real-life scenario: the unfortunate haunting within the Herrmann house. This 1958 happening befell the Herrmann family in Long Island, starting with different bottles around their home opening and spilling their contents all by themselves. At first, the family thought it was a practical joke. This hope was quickly debunked when fluids and containers started moving without outside influence again and again.

There didn't seem to be a genuine clarification as to what was happening, even after law enforcement got involved. The house didn't seem haunted by anyone from its past, since the family was the first to call it home. Paranormal investigators presumed that the ghostly visitors may have been unknowingly drawn in by the Herrmann kids, but seeming to sense the surveillance, the otherworldly occurrences slowed to a stop. The story of Poltergeist follows a similar premise – an unassuming, seemingly perfect home turns into a family's personal hell when their children come into contact with the beyond.

Related: 10 Most Frightening Horror Movies From the '80s

On-Set Controversy and Alleged Curse

JoBeth Williams Poltergeist
MGM/UA Entertainment Co. / United International Pictures

The filming of Poltergeist holds some heaviness in more ways than one. After torrential rain turns the Freelings' new swimming pool into muddy water, coffins and bodies start to float up from the dirt, exposing what's really under the foundation of their home. Thanks to the Beast, Diane unfortunately falls in, and a legion of waterlogged corpses starts bobbing to the surface alongside her. This terrifying sequence really kicked up the scare factor of the film to a whole new level. Unknown to JoBeth Williams until after shooting, she was actually swimming with real skeletons – in the '80s, they were a more inexpensive option than fake rubber ones. And according to Snopes, this is 100% true.

Besides this instance, the overall on-set experience of Poltergeist's cast and crew proved to be an unsavory chapter in the book of horror film history. A real exorcism was even carried out during the filming of Poltergeist II: The Other Side to banish remaining negative energy. The phenomenon known as the Poltergeist curse is unfortunately more fact than fiction, proved by the string of cast members' untimely deaths. Dominique Dunne, who plays older sister Dana, was tragically killed by her ex-boyfriend in 1982 shortly after the film was released. Heather O'Rourke passed away from multiple serious medical issues a few years later. Will Sampson and Julian Beck, featured in the second film in the series, also died from medical complications that same decade.