How They Really Pulled Off These Classic Hollywood Special Effects

We're used to incredible effects in our movies these days. Not only do we believe a man can fly, we believe he can shoot lasers out of his hands, summon lightning from the sky, shrink down to the size of an ant, and blast high-powered photon charges at any approaching enemy — and that's just the Avengers. We watch Pennywise's face break apart like an old clay pot, Daenerys Targaryen decimate an army atop her jet-sized dragon, and Rick Grimes face down an army of the rotting, stumbling dead, and we don't set back in sheer awe, wondering how such a feat of visual splendor was accomplished. We know already: computers. Most of us don't know much in the way of detail beyond that, but we don't need to. At this point in cinematic history, given enough money, manpower, and technological access, we can regularly and reliably make the impossible into the everyday.

But there's something special about old-fashioned special effects. Modern high schoolers still take theater tech classes to learn how to make fake wounds and battle scars. Star Wars is lauded for continuing to employ practical effects. And we return, year after year, to watch the wonders accomplished on screen before CGI was omnipresent. It was arduous work that took hours, often went wrong, and gobbled up money by the walletful, but it resulted in incredible art. Join us as we look back on the high points of special effects in classic Hollywood, and appreciate their feats anew.

Alien is the kind of movie everyone has a favorite moment from. But regardless of whether you're someone who lives for the climax in which the alien gets blown into space or you just love Ripley's cat, chances are you remember the infamous chestburster scene. Even today, when the world is absolutely bursting with movies full of splattery gore (now with pixel-perfect polish), there's still something about seeing that larval horror erupt from a human body. It's gross, it's shocking, and even those who've seen it before brace for its impact every time the scene approaches.

So how did they make it happen? An artificial torso was created, filled with blood and viscera, and manipulated by a puppeteer who operated the monster itself. Actor John Hurt's head and arms were visible above and on either side of the fake torso, which rested upon a table with strategic holes cut into it. Infamously, though the cast knew some details of the scene, they did not know the torso would be spraying blood via hydraulic pumps, and as a result, much of the shock captured on their faces is entirely real. That's right: for once, the actors on screen are just as horrified as the audience. It's no surprise that the scene is considered one of the most memorable in film history.

The Exorcist is full of unforgettable images. There's just something about the contrast between Regan, a young girl in an old-fashioned nightgown, and the more and more deeply depraved acts she engages in, from spider-walking down the stairs to some truly shocking acts of blasphemy. Something terrible and beyond human reason has entered the lovely American home the bulk of the film's action takes place in, and it is terrifying to watch it subvert the normal order.

One of the scariest moments is, in fact, one of the simplest: when the words "HELP ME" appear on the possessed Regan's stomach, as though scrawled from the inside. It's a desperate scream for help, written in the most primal way. Regan is alive, buried in her own body, carving words into her very flesh in the hope of salvation. Of all the effects produced for this movie, it's one of the most convincing — and the most disturbing. The filmmakers created the letters by painting the words onto a foam latex stand-in stomach with cleaning fluid, then heating them with a hair dryer to make them deflate. When played backwards, footage of the process made it look as though the letters were rising, unbidden, to the surface of Regan's belly. A simple process, yet a devastatingly effective one.

The Parent Trap still manages to astound modern audiences with its clever doubling of star Hayley Mills. Even those raised on the 1998 Lindsay Lohan reboot can't quite shake the magical feeling of watching two of the same person in one shot, from an era when computers still took up entire rooms and we were going to space on the computing power of the smartphone in your pocket. There are no shuddery shots or obvious seams, no moment you can point to as the movie showing its age. Almost thirty years passed between the original and the reboot and despite cosmetic and era-appropriate changes, they really didn't have to improve upon the technology of the original incarnation.

How did they do it? Originally, there were only a few moments of trick photography called for. When the sodium vapor process — a method of photochemical processing used extensively by the Walt Disney Studios — was employed, however, the filmmakers were so delighted by the effect that the script was revisited. Notably, the process produces much cleaner results than that of the then-common use of blue screens and contemporary audiences were dazzled by the effects. The process would go on to be used in everything from Mary Poppins to Bedknobs and Broomsticks, and was only retired when computers ushered in a hitherto undreamt-of level of sophistication. But the results don't lie: The Parent Trap still looks great.

Alfred Hitchcock made an everyday animal into a terrifying force of nature in this 1963 horror classic. Who can forget the look in Tippi Hedren's eyes as she cowers in a bird-besieged phone booth? Who can't immediately conjure up the final shots of the thousands of birds perching ominously over town? Birds can be symbols of peace, good fortune, and love, and are often even doted-on pets kept in family homes. But Hitchcock managed to sweep aside those associations in favor of another: birds as carrion creatures with an eternal height advantage, acting according to inscrutable avian desires.

So how did they do it? Well, quite a few of them are actual birds. Some are wild (many of the seagulls were actually rounded up from a garbage dump) and some were borrowed from pet shops. Then came the complicated process of piecing the scenes together. As in The Parent Trap, the sodium vapor process was used to compile shots of the birds attacking. Most impressive was the creation of the scene in which sparrows attack through the chimney. Legendary Disney animator Ub Iwerks took footage of sparrows flying in an enclosed glass booth and superimposed it upon shots of the home's interior, allowing him to multiply them in number and capture their movements with precision. All in all, it adds up to a terrifying movie that forever changed the way a generation would look at crows resting on telephone wires.

Ah, to be a young person abroad. Everything from Eurotrip to Roman Holiday has used this rite of passage as a jumping-off point for great storytelling, but most keep it light, breezy, and focused on freedom. Enter An American Werewolf in London, which combines the trill of adventure and the horror of hungering for human flesh. 

Many elements of the film are impressive, but nothing quite compares to the scene in which protagonist David, once an innocent backpacker and now a cursed abomination, transforms into a werewolf. Suddenly burning hot, he rips off his clothes and watches in horror as his hands and ankles lengthen, hair sprouts across his naked skin, and his skull contorts into a lupine snout. Makeup mastermind Rick Baker and 30 technicians are to thank for this painstaking metamorphosis. The team used prosthetics, rubber masks, and makeup that required ten hours to apply and three to take off to create the tremendous effect. 

Manipulatable body casts were used to make it look as though bones were lengthening, especially during a shot in which David appears to be on his back, seen in his entirety, struggling against his body's rebellion. Actor David Naughton was, in fact, hiding in a hole cut in the set's floor — the "body" we see is a cast. It's no surprise that this film netted Baker an Academy Award and an eternal place in film history.