Punitive institutions for forced labour in the former Soviet Union. The tradition of exiling political protesters and reformers to Siberia was well-established in 19th-century Russia. By a decree of 1919 Lenin maintained such punishment, operating through his police agency, the CHEKA. During Stalin’s rule millions were arrested by the MVD, including peasants who resisted collectivization, Christians, Jews, intellectuals, and political protesters. The prisoners were passed to GULAG (acronym for the Main Administration of Corrective Labour Camps), which was established in 1930 and was responsible for administering the forced labour system. The camps were mostly situated in the east of the Soviet Union and were referred to metaphorically as the “Gulag archipelago”. Estimates of numbers confined to Gulag camps in the years of Stalin vary, ranging between six and 15 million. After the worst years of the purges in the 1930s thousands continued to be sent to the camps. After the arrest and execution of Beria (1953) and the de-Stalinization policy of Khrushchev, there was a decline in the worst excesses of the camps, which were formally replaced in 1955 by Corrective Labour Colonies. Many distinguished Soviet citizens, including the writers Eugenia Ginzberg and Aleksandr Solzhenitsyn, were sent to prison camps; others were “exiled” to Siberia, placed in “psychiatric hospitals”, or in other ways restrained. The physicist Andrei Sakharov and his wife Yelena Bonner were not allowed to leave Nizhny Novgorod (Gorky). In 1987 in the wake of a new policy of glasnost or openness, Gorbachev ordered the release of some intellectual dissidents. All had allegedly been released by 1992.