21st Congress of the CPSU

The 21st Congress of the Communist Party of the Soviet Union took place in Moscow, USSR 27 January - 5 February 1959. It was a mid-term or "Extraordinary" Congress, timed so that Khrushchev could try to consolidate his power over rivals after the attempted coup of the Anti-Party Group in 1957. The Seven-Year Plan of economic development was adopted.

...
Wikipedia