One Million B.C.

No, this is not the Raquel Welch film; that's One Million Years B.C., the remake. The original is One Million B.C. from 1940, starring Victor Mature, Carole Landis, and Lon Chaney Jr. With the alternate title Man and His Mate, it's a Romeo and Juliet story of two prehistoric tribes, one more civilized than the other, who learn each other's ways and eventually join forces to survive the dinosaurs who attack them. 

One Million B.C. was nominated for two Academy Awards: Best Musical Score and Best Special Effects. The dinosaurs are real animals, sometimes dressed in costume like a pig in a triceratops suit. One dinosaur is a man in a suit. The movie led to a protest from the SPCA and a ban on animal cruelty in movies. Therefore, many later dinosaur films reused footage from this one to depict dinosaurs. Footage of the rock slide and volcanoes were reused as well. Despite the expense, One Million B.C. was a box office success. This version is colorized. (Thanks, WTM!)