High Quality Content by WIKIPEDIA articles! The government of the USSR under Stalin murdered many of its own citizens and foreigners. These mass killings were carried out by the security organisations, such as the NKVD, and reached their peak in the Great Purge of 1937-38, when nearly 700,000 were executed by a shot to the base of the skull. Following the demise of the USSR in 1991, many of the killing and burial sites were uncovered.