If they have illegal characters in their XML, I would wager that it's a valid issue.
You can use str_replace() provided that the string is valid UTF-8. Note that str_replace() will then work with byte offsets, so you are no longer dealing with PHP strings but with byte strings.
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.