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The Trial of the Twenty-One was a major Soviet show trial in 1937 in which Grigory Yagoda, the former head of the NKVD, was a defendant. He was charged with treason, terrorism, espionage, and other crimes. The trial was a sham and Yagoda was convicted and executed. The trial was part of a wider campaign of repression in the Soviet Union known as the Great Purge.