The print that I saw -- four times -- the first time in 1976, and then again in 1979, had the Japanese title card, but the subtitles said "Catastrophe: 1999"... I saw the film at the now-defunct Kokusai Theater in San Francisco's Japantown. I also saw the uncut Japanese version of SUBMERSION OF JAPAN there in 1975/76, as well as other odds and ends like WATARI: THE NINJA BOY, LAKE OF DRACULA and EVIL OF DRACULA.
UPA's version, THE LAST DAYS OF PLANET EARTH, was never shown in theaters, since their version was mastered on video tape, not on film.



