The Holocaust was the genocide of European Jews during World War II. Between 1941 and 1945, Nazi Germany and its collaborators systematically murdered some six million Jews across German-occupied Europe, around two-thirds of Europe's Jewish population. The murders were carried out primarily through mass shootings and poison gas in extermination camps, chiefly Auschwitz-Birkenau, Treblinka, Belzec, Sobibor, and Chełmno in occupied Poland. Separate Nazi persecutions killed a similar or larger number of non-Jewish civilians and POWs; the term Holocaust is sometimes used to refer to the persecution of these other groups.

The history of the Jews in Europe spans a period of over two thousand years. Jews, an Israelite tribe from Judea in the Levant, began migrating to Europe just before the rise of the Roman Empire. Although Alexandrian Jews had already migrated to Rome, a notable early event in the history of the Jews in the Roman Empire was the 63 BCE siege of Jerusalem.