These days 50 years ago thousands of delegates assembled in the Kremlin in Moscow to attend the 20th Congress of the Communist Party of the Soviet Union.
It was the first such major event after the death of Joseph Stalin in March 1953.
After the formal end of the congress a special secret session was convened at which the General Secretary Nikita Chrushchev delivered the famous Secret Speech.
It didn't take long for the text of the speech to be available all over the world, and its effect on the Communist regimes everywhere was profound. The man who until recently had been their guiding light, hero and father was suddenly exposed as a dictator of unparalleled brutality.
And since the verdict came from the leadership of the Soviet Communist Party itself, it could not de denounced as propaganda of the class enemy. In fact, what Chrushchev exposed was even worse that what many of the "class enemies" had claimed.
The effects were soon felt throughout the Communist world.
Riots in Poznan in Poland were just the beginning. In October of 1956 Hungary exploded and literally threw the Communists out - only to be brutally surpressed by the Soviet invasion some weeks later. In China, Mao Zedong refused to accept the verdict on Stalin, and quietly the beginning of the rift between the Soviet Union and China began.
The text of the speech - linked here - is still well worth reading. It's undoubtedly one of the most important political speeches of the past century. One can readily understand the effect it had on the delegates. Subsequently, it was read out at closed meetings for party members throughout the Soviet Union.
Still, the speech is very incomplete as a describtion of the communist system. It concentrates on the crimes committed by Stalin during the 1930's against the members of the Soviet Communist party, although some other issues are also dealt with, as his unpreparedness for Hitler's invasion.
But essentially it was meant to create the impression that had everything just stayed with Lenin most things would have been OK.
Now everyone knows better. Brutality and killing was an integral part of the system from the very beginning.
Stalin did not distort the Leninist system - he just developed it further.