WWII Japan plotted to attack U.S. with plague

Japan's Unit 731 is one of the best kept and most horrifying secrets of World War II. Unit 731 experimented on Japanese and Chinese civilians as well as Russian and American POWs during the Second Sino-Japanese War in the 1930s and throughout World War II.

Led by the enigmatic Dr. Shiro Ishii, Unit 731 committed thousands of macabre experiments and infected hundreds of thousands with the plague in China. Most of the scientists involved with Unit 731 escaped trial and entered mainstream society at the end of the war due to an agreement with Allied commanders, but a few are speaking of the horrors they committed in their old age....

During the height of World War II, Unit 731 planned similar biological attacks for the United States. One early proposed mission involved a small kamikaze plane launched from a submarine that would unleash the plague upon the port of San Diego.

The best defined plot, codenamed Cherry Blossoms at Night, aimed to infect the majority of California with the plague during one night in 1945. Another plot involved the use of 10,000 balloon bombs carrying incendiary devices to create forest fires as far inland as Michigan....