I learned all I needed to know about the barbarity of the Germans during WWII by visiting the concentration camps at Dachau and Flossenburg. I will never forget the forboding sense of evil that surrounded Dachau.
Of course, I learned all I needed to know about Islam on 9/11/2001.
Read the book Death March if you can get your hands on it. Incredible book
Back in the 60s, one of my brothers had a school friend whose father was a Bataan Death March survivor. According to my brother, the man would talk a little about WWII, but never about that.