Wearing a military beret, medals and walking with a stick, 90-year-old Samuel Willenberg led a crowd of people through a clearing in the pine forest, stopping sporadically to point out: "And the platform was here, the trains stopped here."

Nothing remains of Treblinka extermination camp apart from the ashes of the estimated 870,000 mostly Jewish men, women and children that the Nazis gassed and buried underground.

On a bright summer's day, with storks nesting nearby, it is hard to imagine the horror that occurred here.

Samuel Willenberg is the last survivor of the Jewish prisoners' revolt in the camp and he had returned for the 70th anniversary....