To broad of a question to answer. A friend of mine made a documentary which eventually netted him sme serious cash for about fifty dollars ...star wars cost what 165 million? Using those figures we come up with an average of 330 thouifand per film but we know that's wildly innacurate.
Too many factors are involved. Salaries, sets, costumes, props, actual film, editors , studio cost, copyrights, promotional materials...its insane.
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.