Oswiecim, Poland ? Pope Benedict XVI visited the Auschwitz concentration camp as “a son of the German people” Sunday and asked God why he remained silent during the “unprecedented mass crimes” of the Holocaust.

Benedict walked along the row of plaques at the Auschwitz-Birkenau complex’s memorial, one in the language of each nationality whose members died there. As he stopped to pray, a light rain stopped and a brilliant rainbow appeared over the camp.

“To speak in this place of horror, in this place where unprecedented mass crimes were committed against God and man, is almost impossible – and it is particularly difficult and troubling for a Christian, for a pope from Germany,” he said later.

“In a place like this, words fail; in the end, there can be only a dread silence, a silence which itself is a heartfelt cry to God: Why, Lord, did you remain silent? How could you tolerate all this?”

Benedict said that just as his predecessor, John Paul II visited the camp as a Pole in 1979, he came as “a son of the German people.”

“The rulers of the Third Reich wanted to crush the entire Jewish people, to cancel it from the register of the peoples of the Earth,” he said, standing near the demolished crematoriums where the Nazis burned the bodies of their victims.

Pope Benedict XVI walks through the gate of the former Nazi concentration camp of Auschwitz in Oswiecim, Poland. Benedict visited Sunday to pay his respects to Holocaust victims.

“By destroying Israel with the Shoah, they ultimately wanted to tear up the taproot of the Christian faith and to replace it with a faith of their own invention.”

Shoah is the Hebrew term for the Holocaust, during which the Nazis killed 6 million Jews.

As many as 1.5 million people, most of them Jews, died at Auschwitz and Birkenau, neighboring camps built by the German occupiers near the Polish town of Oswiecim – Auschwitz in German. Others who died there included Poles, Soviet prisoners of war, Roma – or Gypsies, and political opponents of the Nazis.

Typically, Benedict did not mention his own personal experiences during the war. Raised by his anti-Nazi father, Benedict was enrolled in the Hitler Youth as a teenager against his will and then was drafted into the German army in the last months of the war.

He wrote in his memoirs that he decided to desert in the war’s last days in 1945 and returned to his home in Traunstein in Bavaria, risking summary execution if caught. In the book, he recounted his terror at being briefly stopped by two soldiers.

He was then held for several weeks as a prisoner of war by U.S. forces who occupied his hometown.

Earlier, the white-clad Benedict walked alone under the camp gate containing the notorious words: “Arbeit Macht Frei,” or “Work Sets You Free.”

He stopped for a full minute before the Wall of Death, where the Nazis killed thousands of prisoners. He was handed a lighted candle, which he placed before the wall.

At the Wall of Death, a line of 32 elderly camp survivors awaited Benedict, most of them Catholic. He moved slowly down the line, stopping to talk with each, taking one woman’s face in his hands and kissing one of the men on both cheeks.

Benedict then visited the dark cell in the basement of one of the buildings, the place where St. Maximilian Kolbe, a Polish Franciscan friar, was executed after voluntarily taking the place of a condemned prisoner with a large family in 1941. Kolbe was canonized by John Paul II in 1982.