Part of the filming occurred in the Bronson Caves, known to many history buffs as the Batcave in the Batman television series in the 1960s.
Shot in part in the Caverns of Sonora.
The film is not based on the 1977 science fiction book of the same name by Leo P. Kelley. The book is about two humans who travel back through time to investigate the destruction of a planet.
All the stories of "The Fountain of Youth" involved the State of Florida. They use Texas as the back drop in this movie.