Interviewed artists include famed " Nazi hunter " Simon Wiesenthal ; Ela Weissberger , who survived Terezin , the Nazis ' deceptive " model ghetto , " by performing in a children 's opera ; Dina Gottliebova-Babbitt , who , at Auschwitz , painted portraits of Gypsies for Dr. Josef Mengele ; and Henry Rosmarin , whose harmonica playing for the SS kept him alive .