Alien, the 1979 science fiction directed by Ridley Scott, is regarded by many as one of the greatest films ever made.

The film recently celebrated its 40th anniversary, a time to reflect on a masterpiece that would pioneer the genre for years to come. Upon its initial formation in 1977, Scott was tasked with the challenge of selling the idea to 20th Century Fox—and every other studio—after the majority passed on the script after decided that science fiction was a risky investment.

Initially sceptical, 20th Century Fox offered a budget of $4.2million for the entire project before Scotts’ impressive storyboard presented later in the deal convinced the studio to double their budget in the film.

The story, of course, tells the following story: “In deep space, the crew of the commercial starship Nostromo is awakened from their cryo-sleep capsules halfway through their journey home to investigate a distress call from an alien vessel,” as per the official synopsis. “The terror begins when the crew encounters a nest of eggs inside the alien ship. An organism from inside an egg leaps out and attaches itself to one of the crew, causing him to fall into a coma.”

The film would do on to achieve critical and commercial success upon its release, propelling the careers of Tom Skerritt and Sigourney Weaver to astronomical levels.

While the script and development earned rave reviews, it was the attention to detail in the visual effects which were lauded by Hollywood. Nominated for a huge list of awards following its release, Alien would go on to win the Academy Award for Best Visual Effects at the Oscars that year.

For Scott, however, it was his method of building tension that pleased him most throughout the picture: “Every movement is going to be very slow, very graceful, and the Alien will alter shape so you never really know exactly what he looks like,” Scott once said about his decision to keep the Alien hidden for most of the film.

He added: “I’ve never liked horror films before, because in the end it’s always been a man in a rubber suit. Well, there’s one way to deal with that. The most important thing in a film of this type is not what you see, but the effect of what you think you saw.”

Below, enjoy some behind the scenes images taken from the set.

(Images via Alien Covenant)