The Holocaust, called the Shoah in Hebrew, was the murder of about six million Jews by Nazi Germany and its collaborators, about two-thirds of the Jews of Europe. This course treats it at the center of the war's history rather than as a side story, because the war made it possible and because for the Nazi leadership it was a central aim. Here we trace what happened and how historians explain it.
From exclusion to murder
Persecution came in stages. In 1933 Jews were pushed out of the civil service and many professions. The Nuremberg Laws of 1935 stripped them of citizenship and banned marriage with non-Jews. In the pogrom of 9 to 10 November 1938, known as Kristallnacht, Nazi squads and mobs burned synagogues and wrecked Jewish shops across Germany and Austria, and some 30,000 Jewish men were sent to concentration camps. Many Jews tried to leave, but the world largely closed its doors. At the Evian Conference in July 1938, delegates from 32 countries voiced sympathy, but almost none agreed to admit more refugees. Modern refugee law grew partly out of this failure.
War turned persecution into mass murder. In occupied Poland, Jews were forced into sealed ghettos, where hunger and disease killed tens of thousands; in Warsaw over 400,000 people were crowded into about three square kilometers. After the invasion of the Soviet Union, mobile killing units called Einsatzgruppen carried out mass shootings of Jews, helped by German police battalions, army units and local auxiliaries. At Babi Yar outside Kyiv, nearly 34,000 Jews were shot in two days in September 1941. Shootings in the east eventually killed between 1.5 and 2 million Jews.
From late 1941 the regime built camps designed for killing with gas. Senior officials met at Wannsee in January 1942 to coordinate the deportation of Jews from across Europe. At Belzec, Sobibor and Treblinka, the camps of Operation Reinhard, about 1.7 million people were murdered, nearly all within hours of arrival; these were killing centers with almost no survivors. Auschwitz-Birkenau combined forced labor with mass murder, and about 1.1 million people died there, nearly a million of them Jews.
What the world knew
By late 1942 the Allies had reliable reports of systematic murder, and in December the Allied governments publicly condemned it. In 1944 Jewish organizations urged the bombing of Auschwitz or the railway lines leading to it; the request was turned down as a diversion from military targets. Historians still debate whether bombing would have saved lives or killed prisoners to little effect. Many argue that the larger failure came earlier, in the years when doors to refugees stayed shut.
Other victims
The Nazi racial state targeted others too. Under the program known as T4, doctors and nurses murdered disabled patients in institutions from 1939, and its staff and gassing methods were later used in the death camps. Roma and Sinti were persecuted as a race and killed in large numbers, with estimates from 200,000 to 500,000. Millions of Soviet prisoners and Polish civilians died, and gay men, Jehovah's Witnesses and political opponents were imprisoned in camps where many perished.
Resistance, rescue and explanation
Victims were not passive. In the Warsaw ghetto the historian Emanuel Ringelblum led a secret archive called Oneg Shabbat, whose members buried records in milk cans and metal boxes so the world would know what had happened; much of it was dug up after the war. In April 1943 ghetto fighters rose up and held out against German troops for nearly a month. Rescue was rare but possible. In October 1943 Danish citizens ferried about 7,000 Jews across the water to safety in Sweden, and Israel's Yad Vashem honors rescuers across Europe as Righteous Among the Nations.
How could it happen? For decades historians argued along two lines. Intentionalists stressed Hitler's long-held hatred and saw a plan unfolding from his early writings. Functionalists stressed radicalization driven by competing agencies and local initiatives in a chaotic state, with officials pushing ever further to please their leader. Most scholars now combine the two: Hitler's ideology set the goal and his approval was essential, while the methods emerged through improvisation, rivalry and the war in the east. Christopher Browning's study of one German police battalion found that ordinary middle-aged men, most of whom could have refused without serious punishment, took part in mass shootings, driven by conformity and pressure as much as ideology.
Worked example: reading a deportation timetable
A railway timetable for a special train from a Dutch transit camp lists departure times, car numbers and a destination in Poland. It contains no word about murder. Yet the document needed clerks to schedule the train, engineers to drive it, police to load it and officials to bill the SS for the fares. Asking who touched this paper shows how genocide depended on many people doing ordinary tasks. It also explains why historians speak of perpetrators, bystanders and rescuers, and why the lines between them are not always neat. The lesson for citizens is uncomfortable: great crimes rarely need everyone to hate, only enough people to go along.