Some said Haiti (poorest in America but it isn't south american). Leaving apart Guyana, Surinam and French Guyana, I would say the most undeveloped and poor countries are Bolivia, Paraguay and Peru or Ecuador. I really don't know the poverty rates, because I think Colombia has more poverty than Peru but is more developed.
I think you just don't refer exclusively to poverty rates. More.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.