 To film the large sphere surrounded by a halo in the skies over the city, Bava projected slies of world land-marks onto a opaque silk screen with a brute light behind it.Lucas commented that the object appeared to be "a large sponge with chunks torn out".The shot was then overlaid with multiple exposures which Bava took with his father's Mitchell camera, wound the footage back and shot numerous additional exposures with backyard and home made rocket models.