Roughly 15 years ago, the U.S. Navy surfaced three Ohio-class SSGN missile submarines in a warning to China. However powerful a message that was over a decade ago, the military balance between Washington and Beijing has shifted.

Nuclear-powered submarines use some of the most advanced military technology in the world. These are the ones that are a cut above all the rest.

China's surface navy is growing at a rapid pace as busy shipyards turn out new warships, but the US maintains an edge underwater with its submarines.

Japan's Defense Ministry said the country faces "the most severe and complex security environment" since World War II.