After admiring and being inspired by the ground-breaking work of Willis H. O'Brien in Kong Kong (1933) and the work of special-effects animator George Pal in the 1940s, Ray Harryhausen was able to work on Mighty Joe Young (1949), one of O'Brien's final projects (for which O'Brien won a Best Visual Effects Oscar) although Harryhausen wasn't really credited for most of the work.

Besides the films already mentioned in the 1950s, master of stop-motion animation Ray Harryhausen (often teamed with long-time producer Charles Schneer) turned to mythologically-tainted science-fiction films (including three Sinbad films) to display his painstaking, classic craft of special effects - animated frame-by-frame, until the special effects revolution ushered in by Star Wars (1977) swept through the industry. Harryhausen, who never received an Oscar nomination, did receive the Gordon E. Sawyer Honorary Academy Award in 1992. He created the fantastic images in 15 films between 1953 and 1981, including:

[Pixar's Monsters, Inc. (2001) paid tribute to Harryhausen by having Monstropolis' chic night spot restaurant named after him. Also, the octopus behind the bar in Harryhausen's Sushi restaurant had only six legs, another clever in-reference. Tim Burton also paid homage to Harryhausen in his films, including Corpse Bride (2005).]

Some 60's Sci-Fi Films:

In the 1960s, producer George Pal and director Byron Haskin teamed again to deliver a sci-fi version of Defoe's classic novel, Robinson Crusoe on Mars (1964), about a stranded astronaut on the planet of Mars, with only a monkey named Mona as a companion. Another stranded astronauts film, this time on the Moon after a retro-rocket failed to return them to Earth (foreshadowing the Apollo 13 disaster and its telling in the film version Apollo 13 (1995)), was director John Sturges' Marooned (1969) - that won an Academy Award for Best Visual Effects. And director Richard Fleischer's fanciful Fantastic Voyage (1966), from Isaac Asimov's novel, put a medical team of shrunken explorers (Stephen Boyd and Raquel Welch) inside a human body in a miniaturized submarine that traveled through the blood stream, with a mission to wipe out a dangerous blood clot in the brain of an atomic scientist, while being confronted by the body's natural defense system. Roger Vadim's futuristic space fantasy Barbarella (1968), derived from a comic strip, featured a sexually-emancipated 41st century space adventuress (Jane Fonda), with a memorable striptease under the credits and John Phillip Law as the blind angel Pygar.

Sci-Fi Flops and Turkeys:

There were also any number of dreadfully grotesque, cheesy low-budget science-fiction flops or turkeys - now often regarded as kitsch or cult classics, drive-in specials, or as "the most enjoyable bad films of all time." [Many of these films would eventually end up on the satirical TV show Mystery Science Theatre 3000.] They included some of the following:

• Arthur Hilton's 3-D Cat-Women of the Moon (1953) about scantily-clad Amazons on the lunar surface (advertised as "Love-Starved Moon Maidens on the Prowl!")
• director Phil Tucker's incredible 3-D Robot Monster (1953) (aka Monsters from the Moon) - the sex-starved Ro-Man monster was played by a man in a gorilla suit with a diving helmet; upon release, this famed 'turkey' was so heavily scorned and criticized that Tucker committed an unsuccessful suicide
• Bride of the Monster (1956), with an aged Bela Lugosi playing a mad scientist; one of writer/producer/director Ed Wood's awful classics
• Ed Wood Jr.'s legendary Plan 9 From Outer Space (1956), about space aliens conquering Earth by resurrecting the dead; often considered the worst sci-fi film ever made
• the creature feature The Mole People (1956) about an ancient Sumerian-like, underground group of albinos located in the Middle East during a subterranean, anthropological expedition led by John Agar
• John Sherwood's The Monolith Monsters (1957), based on a story by Jack Arnold (who directed Creature from the Black Lagoon), with giant, menacing black rocks formed from meteor fragments
• Arnold Laven's The Monster That Challenged the World (1957), a classic B-movie creature-feature about giant, prehistoric killer sea mollusks (discovered under S. California's Salton Sea) with snapping mandibles, and with aging western film actor Tim Holt in the male romantic lead role
• the preposterous schlock film Attack of the 50-Ft. Woman (1958, 1993) about a gigantic woman (Allison Hayes) in a bikini
• Attack of the Giant Leeches (1958), a typical representation of a cheap Roger Corman-produced film, about marauding giant leeches in a swamp
• The Wild Women of Wongo (1958)
• The Brain from Planet Arous (1958), about a huge floating alien brain set to take over the Earth
• Tom Graeff's alien invasion film Teenagers from Outer Space (1959)
• Robert Hutton's The Slime People (1963), shot cheaply in a Los Angeles butcher shop; about prehistoric monsters in deep freeze cabinets that were awakened from hibernation by atomic testing
• Roger Corman's disturbing and grotesque sci-fi/horror film, "X" - The Man with the X-Ray Eyes (1963), with Ray Milland as Dr. Xavier, a hubris-filled surgeon whose powers of X-ray vision became self-destructive, causing him to tear out his rotted eyes when a tent evangelist in a revival meeting exhorted his audience to pluck out an offending eye (from the Biblical quote Mark 9:47)
• El Paso fertilizer salesman Hal Warren's Manos: The Hands of Fate (1966), his sole directorial effort (he also wrote and produced), has been mocked as one of the worst films ever made by the Mystery Science Theater 3000 TV show (their most popular episode ever) - it featured out-of-focus scenes, ultra-repetitive dialogue, a badly-dubbed soundtrack, long and drawn-out scenes, and amateur actors; its characters included a half-man, half-goat individual named Torgo and a mysterious cult leader character named the Master [The below standard B-grade film's notoriety even led to a short Canadian documentary titled Hotel Torgo (2004), made by Niagara College film students about the turbulent making of the film]
• and another of the worst films ever made - the sci-fi parody Attack of the Killer Tomatoes (1980)

Time Travel Films:

A number of time travel films have been produced over the years:

• producer/director George Pal's classic film adaptation of H. G. Wells' 1895 novel with Oscar-winning Special Effects, The Time Machine (1960) in which a turn-of-the-century English time traveler and inventor H.G. "George" Wells (Rod Taylor) went to the year 802,701 (past three world wars) to find a most-unusual world populated with peaceful Eloi and monstrous green Morlocks
• La Jetee (1962, Fr.), the landmark, eloquent short French film from director Chris Marker composed entirely of B/W still frames; set after WWIII, about a group of scientists who attempted to send a man back in time to his life before the war; remade as 12 Monkeys (1995) - see below
• the fantasy-biopic Time After Time (1979), director Nicholas Meyer's directorial debut film, in which a young H. G. Wells (portrayed by Malcom McDowell) pursued Jack the Ripper through late 70s San Francisco
• The Final Countdown (1980), in which the USS Nimitz, a modern-day aircraft carrier, was sent back to the Pacific Ocean by time warp to December 6, 1941 (pre Pearl Harbor)
• Somewhere in Time (1980), an old-fashioned, dramatic love story conducted across time and based upon Richard Matheson's novel Bid Time Return; aspiring playwright/actor (Christopher Reeves) willed himself back to 1912 to a turn of the century hotel after falling in love with the picture of an actress (Jane Seymour) given him by an elderly woman who beckoned: "Come back to me"
• Time Bandits (1981), Terry Gilliam's sci-fi fantasy in which six renegade dwarves and a British schoolboy traveled through history after entering a time portal
• The Terminator (1984) and Terminator 2: Judgment Day (1991), see further below
• The Planet of the Apes series, see further below
• Back to the Future (1985), Back to the Future II (1989), and Back to the Future III (1990), three entertaining and popular films in which Marty McFly traveled backwards and forwards in time with the help of mad scientist Doc Brown (Christopher Lloyd) and a super-adapted Delorean vehicle
• Star Trek IV: The Voyage Home (1986), in which the Enterprise crew of the 23rd century journeyed back to 1986 San Francisco in a captured Klingon spaceship to save the Earth's humpbacked whales
• the mega-blockbuster Total Recall (1990), from director Paul Verhoeven and adapted from Philip Dick's short story We Can Remember It For You Wholesale; it starred Arnold Schwarzenegger as a 22nd century construction worker named Doug Quaid who visited a memory-implant travel service to transport him to Mars for an adventure trip as an agent; he discovered that he really was a secret agent and that his entire life as Quaid was a set of artificial implanted memories
• Freejack (1992), in this time-travel chase movie from director Geoff Murphy, a 1991 race car driver (Emilio Estevez) was abruptly transported to the year 2009 by a 21st century bounty hunter (Mick Jagger)
• Timecop (1994), a futuristic action film from Peter Hyams in which Jean Claude Van Damme had the role of a special unit cop in the Time Enforcement Division, an agency to protect against the misuse of time travel
• 12 Monkeys (1995), director Terry Gilliam's mind-bending story, a remake of Chris Marker's short film La Jetée/The Pier (1962, Fr.), was set in a disease and plague-ravaged world due to biological terrorism, forcing the human race to live in miserable conditions below the surface of the Earth; in the year 2035, prisoner Bruce Willis was sent back twice to the 1990s to prevent the 'Army of the 12 Monkeys' from instigating their plot to spread a devastating plague
• Star Trek: First Contact (1996), the 8th film in the series (that began in 1979), with interplanetary time travel from the 24th century to the mid-21st century
• Retroactive (1997), a sci-fi thriller about repeated attempts to change a violent act in the past, through time-travel, that ended up even more disastrous

The Alien Films:

Ridley Scott's effective and influential horror/sci-fi film Alien (1979) - the last major sci-fi film of the 70s, was a unique combination of Spielberg's Jaws (1975) and Carpenter's horror film Halloween (1978). However, it was actually based on A.E. Van Vogt's 1939 short story "Black Destroyer," found in his 1950 collection titled "Voyage of the Space Beagle." 

Alien featured H. R. Giger's unique alien design - a dilapidated mining space vehicle Nostromo, a deadly extra-terrestrial life form stowaway, and a shocking and repulsive chest-bursting sequence involving John Hurt. It appeared that the alien monster may have arisen from the unconscious of its victims. Scott's film spawned other renditions in the four-part series:

• writer/director James Cameron's suspenseful, tense and non-stop action sequel Aliens (1986) about the futile nightmarish battle between Marines and the fertile Mother of rapacious aliens
• David Fincher's Alien 3 (1992)
• Jean-Pierre Jeunet's Alien Resurrection (1997)

Paul W.S. Anderson's Alien Vs. Predator (2004), set in 2004, crossed the Alien franchise with the Predator's (two films in 1987 and 1990); it was the only film not to feature Lt. Ellen Ripley (Sigourney Weaver). A second follow-up film was Alien Vs. Predator Requiem (2007).