Latitude Zero (緯度0大作戦, Ido Zero Daisakusen, lit. ’The Great Latitude 0 Operation’) is a 1969 tokusatsu science fiction film directed by Ishirō Honda, with special effects by Eiji Tsuburaya. An international co-production of Japan and the United States, it stars Joseph Cotten, Cesar Romero, Akira Takarada, Masumi Okada, Richard Jaeckel, Patricia Medina, and Akihiko Hirata.

Three men—Dr. Ken Tashiro, Dr. Jules Masson, and journalist Perry Lawton—are trapped in a bathysphere due to seismic activity. They are rescued by the crew of the supersubmarine Alpha, captained by Craig McKenzie, whom they learn is over 200 years old (and that the Alpha was launched in the early 19th century). McKenzie takes them to Latitude Zero to heal Dr. Masson’s injuries. Along the way, they are attacked by a rival supersubmarine, the Black Shark, captained by Kuroiga, who works for a rival of McKenzie’s, Dr. Malic. Using super-technology, McKenzie gives the Black Shark the slip.