Imperial War Museum, Longon, UK
Under the cover of the Second World War, for the sake of their "new order," the Nazis sought to destroy all the Jews of Europe. For the first time in history, industrial methods were used for the mass extermination of a whole people. Six million were murdered, including 1,500,000 children. This event is called the Holocaust.

The Nazis enslaved and murdered millions of others as well. Gypsies, people with physical and mental disabilities, Poles, Soviet prisoners of war, trade unionists, political opponents, prisoners of conscience, homosexuals, and others were killed in vast numbers.

United States Holocaust Memorial Museum, Washington, DC, USA
The Holocaust refers to a specific genocidal event in twentieth-century history: the state-sponsored, systematic persecution and annihilation of European Jewry by Nazi Germany and its collaborators between 1933 and 1945. Jews were the primary victims - 6 million were murdered; Gypsies, the handicapped, and Poles were also targeted for destruction or decimation for racial, ethnic, or national reasons. Millions more, including homosexuals, Jehovah's Witnesses, Soviet prisoners of war, and political dissidents, also suffered grievous oppression and death under Nazi tyranny.

Yad Vashem, Jerusalem, Israel
The Holocaust was the murder of approximately six million Jews by the Nazis and their collaborators. Between the German invasion of the Soviet Union in the summer of 1941 and the end of the war in Europe in May 1945, Nazi Germany and its accomplices strove to murder every Jew under their domination. Because Nazi discrimination against the Jews began with Hitler's accession to power in January 1933, many historians consider this the start of the Holocaust era. The Jews were not the only victims of Hitler's regime, but they were the only group that the Nazis sought to destroy entirely.

In 1948, the United Nations defined genocide as any of the following acts committed with intent to destroy, in whole or in part, a national, ethnic, racial, or religious group, including:
-killing members of the group
-causing serious bodily or mental harm to members of the group
-deliberately inflicting on the group conditions of life calculated to bring about its physical destruction in whole or in part
-imposing measures intended to prevent births within the group
-forcibly transferring children of the group to another group