10. Soviet Massacres in Eastern Europe (e.g., Katyn)
In 1940, the Soviet Union executed approximately 22,000 Polish military officers, police officers, and intelligentsia in the Katyn Forest, Kalinin, and Kharkiv prisons. This mass execution, known as the Katyn Massacre, was ordered by Joseph Stalin and carried out by the NKVD. For decades, Soviet authorities denied responsibility, attributing the killings to Nazi Germany. It wasn’t until 1990 that the Soviet government officially acknowledged its role in the massacre (britannica.com).
