On the brink of World War II, the emergence of effective radar systems, as well as the development of submarines and carrier-borne aviation, drastically changed the nature of naval warfare. Even the most innovative doctrines became hopelessly obsolete on the battlefields of the new war. In this video, we'll tell you about the navies of the leading naval powers of that time—their composition; number of ships; and the ratio of the main ship types, such as battleships, cruisers, destroyers, aircraf