This was promoted as Hammer Studios' one hundredth production.

Raquel Welch refers to this - one of her most popular movies - as "that silly dinosaur movie".

As the Shell People are attacked by a giant turtle, the women call it "Achelon", the real scientific name for the animal.

Ursula Andress was offered the role of Loana, but passed on the project due to salary demands.

The limited Hammer Studios budget for this movie is in evidence during the Archelon turtle scene. Animator Ray Harryhausen, who could keep seven Hydra heads, or seven skeleton warriors in flowing motion at one time, didn't bother to animate the archelon's hind legs, which simply dragged along in the sand.

A poster of Raquel Welch from this movie was featured in The Shawshank Redemption (1994).

Raquel Welch's grunting was voice-dubbed by Nikki Van der Zyl.

Ray Harryhausen used his "Dynamation" effects technique in this movie, but because Producer Charles H. Schneer owned the brand name, Hammer Studios could not use it in their marketing. However, Producer Michael Carreras wanted to come-up with a similar-sounding name for the process. After originally planning on shooting the movie in Panavision (to which Harryhausen objected, as he, Director Don Chaffey, and Director of Photography Wilkie Cooper preferred the regular spherical process favored by Ray), Carreras, Hammer Studios, and Twentieth Century Fox attempted an amalgamation of the Panavision and Dynamation brand names into a new one, "Giant Panamation". However, the "Giant Panamation" name was dropped when the Panavision company objected to it. Some early press material did, however, use the name.

To off-set the high costs of making this movie, the sets and costumes were used in Prehistoric Women (1967). aka Slave Girls.

The exterior scenes were filmed in the Canary Islands at the end of 1965. Principal photography finished in January 1966, with Ray Harryhausen completing his visual effects by spring.

Robert Brown wore make-up identical to that worn by Lon Chaney, Jr. in One Million B.C. (1940).

Martine Beswick said that she and Raquel Welch got along great during filming. She also said they were offered stunt doubles to do their fight scene, but she and Welch insisted they do it themselves.

John Richardson's love interest in this movie was Raquel Welch. In real-life, he married co-star Martine Beswick.

Martine Beswick said that she and co-star John Richardson fell madly in love at first sight on-set and were together for seven years.

In WarGames (1983), the Triceratops versus Ceratosaurus battle was shown by Professor Stephen Falken (John Wood) to David Lightman (Matthew Broderick) and Jennifer Mack (Ally Sheedy).

It is interesting to note that, in the twenty-six-year partnership between Producer Charles H. Schneer and Special Effects Artist Ray Harryhausen, this is one of just two movies (the other being The Animal World (1956)) of Harryhausen's work during that time frame which Schneer did not produce.

Martine Beswick said in an interview that she didn't have to audition for this movie. Being a Bond Girl opened doors for her and Hammer Studios thought she should join their family, so they offered her the role.

Martine Beswick said the fur bikinis were very uncomfortable. The actresses were constantly in the water, so the bikinis dripped, stuck to them, and got very heavy.

To off-set the cost of one hundred forty thousand pounds sterling, the costumes and sets were re-used in Prehistoric Women (1967).

(At around twelve minutes) A caveman screams, opening wide to reveal a mouth full of cavities.

The main character runs into a giant lizard which unlike the other creatures of the film, is footage of an actual lizard and not stop motion. This is a reference to the original One Million Years BC (1940) which used this method to portray its dinosaurs.

Mentioned in the trailer for A Nymphoid Barbarian in Dinosaur Hell (1990).

The Spanish DVD (U.S. Version) runs one hour and twenty-eight minutes. The U.K. DVD (Uncut Version) runs one hour and forty minutes.

Opening credits: The characters and incidents portrayed and the names used herein are fictitious and any similarity to the names character or history of any person is entirely accidental and unintentional.

A scene where cavemen are crushed by boulders was later used as footage during the 9th Symphony Fantasy Sequence in A Clockwork Orange (1971)