A common trend in stock prices can range from complex to simple. A simple trend would be that they have all gone up, due to inflation. This means due to currency value being lower over time, the stock prices will inevitably go up to compensate the lowering value.
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.