In a Stuttgart classroom in the 1970s, seventh-grader Kai Höss learned something that would change his life. A teacher was reading from a history textbook about the Holocaust when the name “Rudolf Höss” came up. Kai went home and asked his mother if there was any relation. She confirmed that Rudolf was his grandfather — and a Nazi SS officer and Auschwitz commandant who was responsible for the deaths of 1.1 million people, mostly Jews. 6 Kai Höss’ grandfather ordered subordinates to herd prisoners into the “showers” at Auschwitz where lethal clouds of poison Zyklon-B gas were released. Getty Images...