In the winter of 1941, a Jewish gravedigger from Chelmo, the western province of Poland, appeared in Warsaw and desperately sought a meeting with Jewish leaders.
He told them the Nazis were rounding up Jews, including the old, women and children, and forcing them into what looked like tightly sealed buses. The buses had the exhaust pipes redirected into the cabins. The Jews were killed with carbon monoxide. He had helped dig the mass graves for thousands of corpses until he escaped.
On the way to Warsaw, he had gone from village to village, frantically warning the Jews. Scores of Jews, in the villages and ultimately in Warsaw, heard his testimony of horror and dismissed it.
A handful of listeners, however, including Zivia Lubetkin, who two years later would help lead the uprising by 500 armed Jewish fighters in the Warsaw Ghetto, instantly understood the ultimate aims of the Nazi state.