Quoc: 20 Million Miles to Earth began production in Rome, Italy in September 1956, using only William Hopper of the main cast, and moved to the U.S. from October 30 to November 9 of that year. Rome was chosen as the location for filming because Harryhausen wanted to vacation there. The working title of the film was The Giant Ymir, and it has also been released as The Beast from Space. All references to the name Ymir were removed from the released version of the film, as Harryhausen was concerned that audiences might confuse it with the Arabic title "Emir".

Answer this question based on the passage: where was 20 million miles to earth filmed?
HW Chung: OK, some thoughts:
This is the relevant information: 20 Million Miles to Earth began production in Rome, Italy in September 1956, using only William Hopper of the main cast, and moved to the U.S. from October 30 to November 9 of that year. The answer is Rome , Italy.