After user clicks allow, the browser is redirected to my server, without facebook iframe?

You're specifying the URL yourself as part of the auth process - if you want to send them to your app's canvas, use that as the URL.

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.