With the international (including Italy) success of large-scale, effects-laden science-fiction spectacles from Japan, such as Ishirô Honda's The Mysterians (1957) and Battle in Outer Space (1959), Italian producers had hoped to duplicate their success with this, Italy's first big space opera.
Ultra Film had so much faith in the science-fiction genre that it immediately re-teamed director Antonio Margheriti and writer Ennio De Concini to do a second film, Battle of the Worlds (1961).
Takes place in 2116.
The dialogue between Lucy and Ray Peterson about the purpose of "flowers" is used as the intro to DJ Okawari's popular song "Flower Dance".