After the death of Josef Stalin in 1953, little criticism regarding his leadership was tolerated until, in a closed session of 1,500 delegates and visitors in 1956 First Secretary of the Communist Party Nikita Khrushchev denounced The Personality Cult of Josef Stalin and its Consequences.
Khrushchev accused the cult of personality around Stalin for serious crimes, including the execution, torture and imprisonment of loyal party members on false charges.
Krushchev accused Stalin of foreign policy errors, failing Soviet agriculture, ordering mass terror and for making mistakes that led to German occupation of huge areas of Soviet territory and the appalling loss of life in the Second World War.
At a party congress in 1961 Khrushchev repeated his attack on Stalin’s memory in open session. Other speakers then rose to denounce Stalin’s crimes.
Stalin’s body was removed from its place alongside Lenin in the mausoleum in Red Square, and names such as Stalingrad were changed.
Source: historytoday.com