BBC Radio 4's Reconciling Histories
At the end of May nearly 300 Israelis - half Israeli Arabs, half Jews - travelled to Auschwitz to learn more about the Holocaust and try to help heal the wounds of the present conflict in the Middle East.
They talked in whispers as if it was too painful to speak about the horror out loud.
The Nazis killed nearly six million Jews across Europe
They hugged each other and sobbed - a group of Israeli Jews and Israeli Arabs together sharing the pain of the Holocaust.
"How many people walked here in this place, how many women cried for their children," said Hyam Tannous, an Arab, clearly distressed.
"It's shocking, shocking," said Thabet Abu Rass as we stood in the gloom of an echoey gas chamber.
"Here in this room I cannot imagine how they pushed you to this place, 800 people together and then using the gas."
He couldn't finish his sentence. Lost for words, he turned away and stared at the wall.
This trip to seek reconciliation through trying to understand the Jewish pain of the Holocaust was the idea of a Greek Catholic priest from the Arab town of Nazareth.
He is one of the 1.2 million Palestinians who don't live in Gaza or the West Bank, but who are Israeli citizens.
Father Emile Shoufani had watched as trust between Jews and Arabs in Israel was crushed in the violence of the intifada, or uprising.
If this is not co-existence and peace for heaven's sake what is?
But he made an extraordinary and unconditional offer to the Jewish community: let Israeli Arabs try to understand the pain of the Holocaust, as a way of bridging the gap between the communities.
The idea of the trip was controversial, with criticism from both sides.
"What, you're going to Auschwitz with Arabs? That's like blasphemy," one Jew was told by an acquaintance.
One Israeli Arab said to another: "Why are you bothering with the suffering of the Jews? We've lost our land, we've our own pain to deal with."
But the trip went ahead.
And from the start it was clear something special was taking place.
In a synagogue in Krakow, Father Emile wore a Jewish skullcap - a yarmulke - as a symbol of solidarity. Israeli Arabs stood shoulder to shoulder with Holocaust survivors.
The trip was the idea of Father Emile Shoufani (right, with Thabet Abu Rass)
For Jewish couple Gabi Salomon and Esti Niman it was a breathtaking moment.
"To see these people on stage," said Gabi. "If this is not co-existence and peace for heaven's sake what is?"
He started to cry. "If we can create it here, why can't we do anything beyond the boundaries of this place? This is not even a dream come true because I've never dreamt such things were possible."
It took courage from the Jews to share their innermost grief, and courage from the Arabs not to shy away.
During two long and harrowing days in the camps at Auschwitz and Birkenau the enormity of the Holocaust became real.
Close to six million Jews across Europe were murdered by the Nazis - roughly the total population of Israel today.
Ester Golan's mother was one of around 1.25 million who died here.
It was an emotional experience for Gabi Salomon (left) and Esti Niman
When she broke down, an Arab woman put her arm around her.
"This is a one-time opportunity," said Ester. "It's never happened before, and when I see one of the Arabs cry I put my arms round them."
"Now I understand the fear of the Jews," said Hyam.
"I'm going to recommend all my friends to come here," said Thabet. "All Arabs should understand this."
At the end of the trip, the challenge for Gabi, a Jew going home to Israel, was clear:
"Soon it's going to be our turn to listen to their pain. Here there's a huge difference, we don't blame each other, here there is another enemy, the Nazis.
"But when it comes to talking about the Arabs and their plight it will be our test, to see whether we can acknowledge the pain that the Palestinians suffer for which we are at least in part responsible."
Reconciling Histories is broadcast on BBC Radio 4 at 2000 BST on 5 June.