If you have no java code generation and only need an UML graphical free tool then Papyrus or Topcased is what you need. These are Eclipse plugins and are really good at graphical level because they use the GMF framework.
YEd Graph Editor is pretty neat and free: http://www.yworks.com/en/products_yed_applicationfeatures.html.
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.