Alien (1979), directed by Ridley Scott, is the first in a series of science fiction movies. Although the title characters are the highly aggressive extraterrestrial creatures, the real connecting thread is of the adventures of Ellen Ripley, played by Sigourney Weaver, a human woman who finds herself being the principle opponent of the species through the series. This makes this film series the only major American one with a female central hero.
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In the first film, the crew of the transport ship Nostromo receive a signal which might be of nonhuman origin. They land on a deserted planet and find an ancient ship and the aliens that killed its crew. The eponymous alien creature is a lethal predator with consistently surprising abilities and physical forms, and which reproduces by parasitizing living victims. The life cycle of the alien has been compared to that of the tsetse fly.
Alien has, as of 2003, three sequels:
In 2002 the United States Library of Congress deemed Alien "culturally significant" and selected it for preservation in the National Film Registry.
