Both the Japanese and the Germans had such advanced tech.  Here is yet another example of Japanese sub tech.  They wanted to use these big subs to launch bombing raids into the western US.  Also had plans to release rats with the plague and other such deadly viruses. The US sunk the few that were captured so the Russians wouldn’t get a hold of them.

Hard to imagine a world at war.  Let’s hope it never happens again.  It will be far worse than some rats and bombs I fear.

WWII Japanese sub found off coast of Hawaii.