Calling himself a son of Germany, Pope Benedict XVI prayed at the former Nazi death camp in Auschwitz. The visit was the most poignant moment in the pope's four-day visit to Poland.

Pope Benedict XVI with Poland's President Lech Kaczynski in the Nazi concentration camp Auschwitz

Pope Benedict XVI walked silently past the infamous gate of the Nazi death camp at Auschwitz, under the metal arch reading "Arbeit Macht Frei", German for "Work sets you free".

He stopped in front of the Wall of Death where thousands of prisoners were executed during World War II. He was handed a lighted candle, which he placed before the wall.

Then Benedict XVI walked up to a long line of 32 elderly camp survivors to greet them. He stopped to talk to each one of them. One and one half million people died in Auschwitz during the Nazi regime, most of them Jews.

Solemn music was played. Then the pope prayed in German, the first time he spoke in his native language during this visit to Poland.

He addressed those present, saying it was almost impossible to speak in this place of horror, in this place, he said, where unprecedented mass crimes were committed against God and man.

Words fail here, he said adding that he had to come to Auschwitz to implore the grace of reconciliation from the men and women who suffered here. Benedict said that in the Nazi death camp of Auschwitz-Birkenau humanity walked through a valley of darkness.

Benedict XVI said he came to Auschwitz as a son of the German people. He said he could not fail to come here. He had to come as a son of that people over which a ring of criminals rose to power by false promises of future greatness.

The German pope said this is a place of living memory, and behind the inscriptions he saw, is hidden the fate of countless human beings. He said they show us the terrifying effect of hatred, and help us see evil as evil and to reject it.