Go to google books. Examine the OLD history books and look at the pre-war years.
Take her to the Holocaust museum in Jerusalem. While there, watch the short film entitled “Night and Fog.” Since you mentioned you cannot get there at this time, on the interwebby, search for “Night and Fog.” Show her that.
I’m forewarning you, if you find the movie and show it to her, neither of you will ever be the same.