Alright, I know this has been done to death, but I haven't seen a thread about this in a while and I just watched a documentary about the early 20th century. It talked about imperialism and alliances and all that stuff and they kept mentioning that that period was the closest we have ever gotten to a global war.
So, as you can probably already tell, my question is what if there had been a global war around 1920 or so? What would it have been like? What would be the result? How different would the world today be?