This week marks the 75th anniversary of the liberation of the Auschwitz-Birkenau concentration camp.
We'll be hearing from survivors in Sophie Nahum's series "The Last Ones".
Among them is Henri, a child of Polish migrants, who was arrested in western France when he was only fifteen years old.
He was one of the 878 people leaving on convoy "73" to Kaunas, Lithuania.
Only 22 of them would come back alive.
75 years later, as the only remaining survivor from the convoy, he speaks of the guilt he feels having been one of the few to escape the horror.