This film was advertised with the slogan "See Raquel Welch In Mankind's First Bikini!" While archeologists tell us humans did not live at the same time as dinosaurs, and our prehistoric ancestors probably didn't look much like Ms. Welch and her co-stars, One Million Years B.C. is a good bit more fun than more scientifically accurate portrait of the era might have been. Tumak (John Richardson) of the Rock People is exiled from his tribe after a fight with his father, and after days of endless wandering is in sad shape before he's taken in by the more peaceable Shell People. He attracts the attention of well-proportioned cave woman Loana (Raquel Welch), but once again finds himself a man without a country after his violent nature alienates the Shell People. Along with Raquel (whose character is remarkably well-groomed given the time period), this movie's greatest selling point are the special effects; legendary stop-motion animator Ray Harryhausen created a dazzling collection of prehistoric creatures for this film that still look impressive, even in the more sophisticated era of computer generated imaging technology.
by Mark Deming synopsis