(i) Information about the Nazi practices came out of Germany during the last years of the regime. But, it was only after the war ended and Germany was defeated that the world came to realise the horrors of what had happened.
(ii) The Jews wanted the world to remember the killings and sufferings they had endured during the Nazi killing operations also called the Holocaust.
(iii) The documents left behind by ghetto and camp inhabitants, who wrote diaries, kept notebooks and created archives became the source of knowledge about the Holocaust.