Unless its a typo, your Class method defined as (Photo*) Photo is not implemented (there is a (Photo*) Caption {} method which looks its just an accident.
You are receiving this error because in your header file you declared that there would be a method.
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.