Who'd be your candidate for the most influential person of the 20th century?
(and with 'influential' I mean who had the greatest effect on the biggest number of people, good or bad)
Names coming to mind would be Einstein, Ghandi, Hitler, etc. Does this sound reasonable? I suppose it does. Until you consider the impact that Fritz Haber and Carl Bosch had on the world. The unleashing of the Haber-Bosch process for extracting nitrogen out of the atmosphere have made possible industrial agriculture on a scale never before considered, thereby triggering the population explosion. Ironically, the Haber-Bosch process also considerably prolonged the First World War, resulting in the deaths of millions.
Anybody else through the 20th century that can be considered on this list have had either a moral or technical impact on the world. But if not for Haber and Bosch, billions won't even be around today. Probably the majority of human beings alive today owe their existence directly to these two germans. And that, in my book, is incredibly amazing!
Here's a pretty good link. And do yourself a favour and follow the other links on that page, there's plenty interesting stuff there!