So, believers, if god exists - why has there never been a documented, scientifically proven miracle?

Get away from here, Satan. What you suggest is intentional evil, which shows you live in hate, trying to cause Christians to sin and then accuse us hypocritically. Yet God noted all your words and your anonymous status will not protect you at the Judgement day.

"For by your words you shall be justified, and by your words you shall be condemned." http://biblehub.com/matthew/12-37.htm What you suggest is evil and not necessary. Abraham did not sacrifice his child.

Christians are under New Covenant.

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.