Future Boy Conan.

In this 1979 condensed-for-film recut of Hayao Miyazaki's 1978 anime series, a young boy named Conan goes on a grand adventure. Conan lives in a world that is mostly oceans; the major land masses having been destroyed by the weapons of the great disaster of 2008. He meets a young girl named Lana, who is kidnapped by the technological city-state of Industria as they attempt to regain those weapons. Together with his friends, Conan sets out to rescue Lana and stop Industria from threatening the rest of the world.