Church leaders have remembered the millions of Jews who died at the hands of the Nazi regime.
Thursday marks International Holocaust Memorial Day, held each year on the anniversary of the liberation of the Auschwitz-Birkenau concentration camp on 27 January 1945.
At Wednesday's general audience, Pope Francis called Jews "a suffering people" who "deserve peace".
He said the world must never forget the "extermination of millions of Jews, people of various nationalities and religious faiths" at the hands of the Nazis.
"This unspeakable cruelty must never be repeated," he said.
The Pope, who visited Auschwitz in 2016, said it was especially important to educate younger generations about "the horrors of this dark page in human history".
"It must never be forgotten, so that we can build a future in which human dignity is never again trampled upon," he said.
Around six million European Jews were killed by the Nazis and nearly all of the 1.1 million people who died in Auschwitz were Jews.
The Archbishop of Canterbury, Justin Welby, also remembered those murdered during the Nazi genocide as well as "all subsequent genocides".
He called on people "to stand against persecution because of identity or faith".
"May hatred be replaced by the love of God who calls each person precious," he said.
