Espionage & Resistance

In 1943, the Nazi German forces uncovered mass graves at Katyn Forest near Smolensk, Russia, containing the bodies of approximately 4,400 Polish officers who had been captured by the Soviet Union during the 1939 invasion of Poland. The Polish Underground (Home Army) independently investigated the site and confirmed that it was the Soviets -- not the Germans -- who had committed the massacre. Stalin responded by breaking relations with the Polish government-in-exile and suppressing all information about the massacre. The Soviet Union maintained the official fiction that Germany had committed the killings until 1990.

In May 1945, just days after Germany's surrender, Winston Churchill ordered the destruction of all Ultra intelligence records relating to the British codebreaking operations at Bletchley Park. Churchill feared that if these records were preserved, they would reveal that the Allies had been reading German encrypted communications throughout the war -- a capability that would be essential during the emerging Cold War with the Soviet Union. Many historians believe this decision destroyed irreplaceable historical records of one of the most remarkable intelligence operations in history.