The War of the Gargantuas, released in Japan as Frankenstein's Monsters: Sanda versus Gaira(フランケンシュタインの怪獣 サンダ対ガイラ,Furankenshutain no Kaijū: Sanda tai Gaira), is a 1966 science fiction kaiju film. The film was co-produced between the Japanese company Toho, and Henry G. Saperstein's American company UPA. The film was a sequel to Frankenstein Conquers the World, and was the second of two films featuring giant Frankenstein monsters that Sapertstein's company co-produced with Toho. Directed by Ishirō Honda, and featuring special effects by Eiji Tsuburaya, the film starred Hollywood actor Russ Tamblyn, alongside Japanese actors Kenji Sahara and Kumi Mizuno.