As Adolph Hitler and his armies churned across the continents during World War II, they sent captured citizens and soldiers to concentration camps. For many months, the systematic torture and murder taking place in those camps was hidden behind the cloud of war.
Jan Karski fought for the Polish resistance in Warsaw. He saw the Nazi atrocities and set out to expose Hitler's wrongdoings. In 1943 he began meeting with journalists, religious leaders and politicians, supplying details of the extermination of Jews and other groups across Poland. Karski even spoke with U.S. president Franklin Roosevelt.
Sadly, no one believed his claims initially. The next year, though, he published "Story of a Secret State,"which detailed his accounts. Nearly half a million copies sold, spreading the news of the Holocaust far and wide.