Francis entered the camp on foot, walking slowly in his white robe beneath the notorious gate at Auschwitz bearing the words “Arbeit Macht Frei” (Work will set you free).
After Auschwitz he moved to nearby Birkenau, where people were murdered in factory-like fashion in gas chambers.
It was a contemplative and private visit of nearly two hours that Francis passed in silence, except for a few words he exchanged with camp survivors and Holocaust rescuers.
Vatican and Polish church officials had explained that he wanted to express his sorrow in silence at the site, mourning the victims in quiet prayer and meditation.
However, he did express his feelings, writing in the Auschwitz memorial’s guest book in Spanish: “Lord, have pity on your people. Lord, forgive so much cruelty.”
As an Argentine, he is the first Pope to visit Auschwitz who did not live through the brutality of the Second World War on Europe’s soil.
Both of his predecessors had a personal historical connection to the site, with the first, John Paul II, hailing from Poland and himself a witness to the suffering inflicted on his nation during the German occupation.
His successor Benedict XVI, who visited in 2006, was a German who served in the Hitler Youth for a time as a teenager.
Francis prayed silently for more than 15 minutes before meeting several survivors of the camp, greeting them one by one, shaking their hands and kissing them on the cheeks.
He then carried a large white candle to the Death Wall, where prisoners were executed.
With aides using small flashlights to light his way, Francis visited the underground cell where Franciscan monk Maksymilian Kolbe was killed after offering his life to save a Polish man whom camp handlers had picked to die of starvation.
German occupation forces set up the Auschwitz-Birkenau camp during World War Two in Oswiecim, a town around 70km from Poland’s second city, Krakow, in the country’s south.
Between 1940 and 1945 Auschwitz developed into a vast complex of barracks, workshops, gas chambers and crematoria.
On July 29, 1941, the camp director, in reprisal for the escape of a prisoner, chose 10 others and sentenced them to death by starvation.
When the selection was completed, Kolbe stepped forward and volunteered to die in place of one of them, Franciszek Gajowniczek.
Kolbe was later killed by lethal injection but the man he saved survived the war. He was made a saint in 1982 by then-Pope John Paul II, a Pole.
Yesterday, the 75th anniversary of Kolbe’s sacrifice, Francis also visited Birkenau, a part of the camp where most of the killings were committed in gas chambers.
Invited guests, among them camp survivors and Christian Poles who saved Jews during the war, stood in respect as the Pope arrived, his vehicle driving parallel to the rail tracks once used to transport victims to their deaths.
When Francis arrived, the hundreds of guests applauded. He slowly observed each of the memorial plaques in the 23 languages used by the inmates.
Poland’s chief rabbi, Michael Schudrich, then recited in Hebrew Psalm 130, which starts: “From the depths I have cried out to you, O Lord.”
Francis clasped his hands and bent his head as the psalm was read first by the rabbi and then by a priest in Polish.
The visit to Auschwitz came on the third day of a five-day visit to Poland that includes meetings with young pilgrims taking part in World Youth Day, a global youth celebration.