What Americans know about the Holocaust Most U.S. adults know what the Holocaust was and approximately when it happened, but fewer than half can correctly answer multiple-choice questions about the number of Jews who were murdered or the way Adolf Hitler came to power, according to a new Pew Research Center analysis. When asked to describe in their own words what the Holocaust was, more than eight-in-ten Americans mention the attempted annihilation of the Jewish people or other related topics, such as concentration or death camps, Hitler or the Nazis. Seven-in-ten know that the Holocaust happened between 1930 and 1950.