[3] The film is about an American engineering team led by Bart (Ward Ramsey) building a harbor on a Caribbean island when they accidentally uncover two dinosaurs that have been frozen in suspended animation for millions of years.

After the Tyrannosaurus seemingly kills the Brontosaurus by biting its neck, it notices the humans hiding in the mine and begins furiously kicking and clawing at it.

During special-effects work on this picture, the crew used their Brontosaurus model and miniature jungle set to film a shot for an episode of TV's The Twilight Zone (1959) called "The Odyssey of Flight 33".

The roars and growls of the Tyrannosaurus were used numerous times for creatures in The Outer Limits (1963 TV series) in episodes such as The Invisibles, and can also be heard from various other film monsters.

The leading role was intended for Steve McQueen, who starred in The Blob two years earlier,[5] also produced by Harris and directed by Yeaworth.

The film had its premiere on June 24, 1960, at the Joy Theater in New Orleans and then opened in Cincinnati, Ohio; Hartford, Connecticut; Providence, Rhode Island; Springfield and Worcester, Massachusetts; Cedar Rapids, Iowa; Baton Rouge and Shreveport, Louisiana.

[1][6] Howard Thompson of The New York Times wrote, "If ever there was a tired, synthetic, plodding sample of movie junk, it's this 'epic' about two prehistoric animals hauled from an underwater deep-freeze by some island engineers.