Pandemics are horrifying. But what if one could be unleashed deliberately? How did ancient armies from the Greeks to the Mongol hordes use germ warfare? Why did America conduct tests on unsuspecting people in New York and San Francisco? Can biological weapons be developed to only infect a single person? And why is the US government researching how to use insects as taxis for viruses? ---- Power Corrupts is written and narrated by Brian Klaas. The executive producer and sound editor is George McDonagh.