Close Encounters of the Third Kind
This film is rightly regarded by both viewers and critics as one of the best works ever made by Steven Spielberg. Given the amazing body of work this director has under his belt, that's a huge compliment.
The film tells the story of humans encountering aliens. Unlike other science fiction efforts, this time the visitors from space didn't come to plunder Earth or wipe out humanity, but to make friends. It might sound boring to some, but a brilliant script and excellent performances turned this relatively simple premise into something extraordinary.
Communication with the aliens is portrayed in a playful and entertaining way. This is greatly enhanced by the very good special effects for the time and the excellent musical score by one of Hollywood's greatest composers, John Williams. Thanks to this film, filmmakers began to think about aliens in a different way than they had before.
Alien
While Spielberg introduced peaceful aliens in Close Encounters of the Third Kind, Ridley Scott's Alien took the exact opposite approach. The creature he and his screenwriters created is an unforgiving, terrifying killer with acid for blood.
Scott managed to blend the sci-fi genre with horror in a way that had never been done before. Alien is very minimalist. Most of the action takes place in the cramped corridors of the spaceship Nostromo, which has a huge impact on the film's atmosphere.
Star Wars
In 1977, the first Star Wars hit theaters and took them by storm in an unprecedented way. George Lucas introduced audiences to something they had never seen before. Lightsaber duels, space battles, and shootouts with Imperial troops were so captivating that Star Wars became one of the most successful films of all time. And that was just the beginning.
Today, Star Wars has spawned not only eleven feature films but also a massive number of books, comics, and series. The entire franchise is worth billions of dollars. The only phenomenon that can compete is Harry Potter, and even then, just barely.
Perhaps the biggest competitor within the sci-fi genre is the long-standing rival Star Trek. While it boasts an almost fanatical fanbase and a similarly well-developed universe, it's not nearly as mainstream.