The 1974 horror film, The Texas Chainsaw Massacre, is considered one of the scariest movies of all time. But the movie is also notorious for having had a troubled period of production due to poor conditions on the set.

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Still, the story of the cannibalistic Sawyer clan and the birth of one of horror's deadliest killers, Leatherface, has produced an epic franchise still revered to this day. There have been several sequels and remakes of the original movie but the 1974 film stands the test of time as a classic. Here are 10 interesting details you might not have noticed on your first viewing.

Some of the screaming in the movie was real

It's common knowledge that the 1974 film experienced a troubled production. Between the cast and crew working in intense Texas heat and the long shooting days, the set wasn't exactly a paradise for anyone on it. There are a few instances in the film where the screams of pain or fear you hear from the actors are so visceral because they're all real. During one scene, Gunnar Hansen (who played Leatherface) dropped the chainsaw.

It created friction with the shield on his leg and caused a burning sensation. His scream of pain is very real. Another instance is when Teri McMinn, who plays Pam in the film, is suspended from a meat hook. They used a nylon rope to create the effect. Apparently, it was extremely uncomfortable and cut her between the legs. Her piteous cries were indicative of the very real pain she felt shooting that scene.

That was Marilyn Burns' real blood

Poor Marilyn Burns, who played Sally in the movie, went through a great deal of trauma during filming considering she stayed alive the longest. In one of the film's most famous scenes, Leatherface cuts Sally's finger open. He does this so that Grandpa can drink her blood. As if the family weren't creepy enough, right? Well, Gunnar Hansen had a mechanism to use that was supposed to leave fake blood behind.

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Unfortunately, it malfunctioned. Hansen wound up using a razor blade to genuinely cut open Marilyn's finger. The actor who played Grandpa was actually drinking her blood. To be fair, at that point the actors just wanted to get through the scene and were willing to do whatever it took to make that happen.

The climactic dinner scene was just as terrifying as it looks on-screen

The dinner scene is one of the most horrifying and iconic in the film. It features a bound Sally being tormented by the Sawyer family while Leatherface serves them a meal. Grandpa sucks blood from her finger and tries to kill her with a hammer, as it becomes increasingly obvious that Sally may become the next item on the menu. But in real life, the scene was terrible to film.

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It was reported that everyone on set was starting to become delirious and Hansen even claims that, at one point, he felt himself becoming Leatherface and genuinely considered murdering Marilyn Burns. It's not surprising that this happened given the immense heat and the stench of real corpses and bodily odors coupled with the long shooting hours. It was hardly a fun set to be on.

It's really not as graphic as you would expect

Leatherface wielding a chainsaw in The Texas Chain Saw Massacre

When you start watching a movie called The Texas Chainsaw Massacre, you probably expect a certain amount of, well, blood and gore. The killer wields a chainsaw which creates much bloodier results than a knife. However, the movie is surprisingly lacking in blood.

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The reason is that Tobe Hooper wanted to try and get a PG rating for the movie. It goes to show you don't need gore to create a truly terrifying experience because no one in their right mind would rate this film PG. It's extremely uncomfortable and tense, even without graphic kill shots.

Most of the animal carnage you see is real

The movie was made on a shoestring budget. It was cheaper to use real animal corpses and at least one real skeleton than it was to buy fake ones. That means the cast and crew were forced to shoot and work in an environment ripe with the scent of death and decay.

Given the real nature of the corpses and the scorching Texas heat, you can imagine how terrible the stench was and why the production of this movie was so difficult.

The car graveyard

Leatherface wielding a chainsaw in Texas Chainsaw Massacre's Leatherface 1974

Early on in the film before Kirk and Pam arrive at the house that will eventually be their downfall, they pass an abandoned lot full of old cars. This is something explored more in the 2003 remake of the movie.

If there was any doubt in your mind about the travelers being the first group slaughtered by the Sawyer clan then the graveyard of abandoned vehicles should seal the deal. Clearly, Leatherface has been butchering people long before the characters of this movie came along. The subtle implication as opposed to outright stating it helps add to the movie's deep sense of foreboding.

Leatherface wears three different masks in the movie

Next time you watch the movie, make sure you pay attention to the mask Leatherface is wearing in any given scene. The masks are indicative of his mood in each scene. He has three masks he wears in the 1974 film, his killing mask, the mask of a "pretty woman," and that of an old lady.

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He wears the old lady mask when trying to be domestic, such as during the dinner scene. The killing mask is obviously his choice when he's going on a murder spree. The pretty woman mask is more about him paying homage to how he grew up.

That was a working chainsaw

In some scenes in the movie, Gunnar Hansen was forced to wield a working chainsaw. The reason is that they wanted to get specific effects that could only be done by the real tool rather than a fake. Hansen spoke about using a real weapon in the past.

Entertainment Weekly quotes him saying, “It was very dangerous. I had no idea how dangerous it was until later after the movie came out when I was living in the woods and chopping up wood to heat the house.” You can imagine how difficult and bulk it must have been for the actor to run around with a heavy, working, chainsaw.

The iconic shot of Pam has a darker meaning

The photo of Pam approaching the house is one of the most iconic shots from the film. Even though Texas Chainsaw is known as a disturbing horror movie, it also has some beautifully textured frames that utilize the natural splendor of the outdoors.

The photo of Pam also stands out because it shows her entire back. At first, it might seem like a way to add eye candy to the movie but when you reconsider the purpose, it's an example of foreshadowing. Pam eventually meets a hideous fate involving a meat hook, and where does the hook go? Exactly.

Everyone wore the same outfits every day

Sally in the truck at the end of Texas Chainsaw Massacre

Notice how no one changes their outfits? That makes sense because the film only takes place over a short period of time... but there's another reason for it. The film couldn't afford a huge wardrobe budget so the actors had to wear the same outfits every day.

You can see why the production of this movie was so harrowing. Everyone probably stunk to high heavens after being out in the hot weather all day every day and not able to change their clothes. It wouldn't be fun to put on the same sweaty shirt you wore the day before, for days on end. At the end of the film when you see Sally covered in blood escaping in the truck, her shirt was so covered with Karo syrup (fake blood) that it had become completely stiff.

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