The killing of about six million Jews by the Nazi authority and their allies during World War II is known as the Holocaust (Shoah).
The Nazis tried to exterminate every Jew in Europe between 1941 and 1945. Jews were either sent to concentration camps or killed by Einsatzgruppen, execution squads.
Of the eleven million Jews in Europe, six million died. Most of the Holocaust took place in Eastern Europe, in nations like Poland and Ukraine.
The deliberate killing of Roma also falls under the definition of the word “Holocaust.” Disabled individuals, Soviet POWs and civilians, Polish civilians, homosexuals, socialists, communists and trade unionists, Freemasons, and Jehovah’s Witnesses were among the other groups targeted by the Nazi authority.
Nazism was a group effort. Lithuania and the Ukraine, two nations that the Nazis had conquered during World War II, helped the culprits.
PIC: NBC News, Wikipedia, Holocaust Encyclopedia- United States Holocaust Memoriam Museum, The Council of Europe