I suppose it'd be better if the thought would actually come from yourself (well it isn't bad to ask for others' opinion but just saying) so that the idea is from your heart and would not regret it later on after thinking of something better than what you have heard or read from suggestions furthermore tattoo is a very special thing a form of art that would stay with you forever unless you have it taken off.
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.