Top 5 Soviet abbreviations you need to know

Abbreviations have become an integral part of the Russian language, and it is impossible to imagine not using them these days.
“A whole boom of new abbreviations appeared in the Russian language during the Soviet period. Opponents of the Soviet system often claim that numerous abbreviations were part of a ridiculous and discordant totalitarian 'newspeak',” Gramota.ru (Грамота.ру) editor Andrei Gorshkov says.
1. ВКП(б) (VKPb)
This abbreviation actually means the Bolsheviks. It’s the All-Union Communist Party of Bolsheviks, or Всесоюзная коммунистическая партия (большевиков): this is how the Communist Party was called in 1925-1952, after which it was renamed into the Communist Party of the Soviet Union.
2. КГБ (KGB)
This one is really well known to many. It comes from Комитет Государственной Безопасности, which is Committee for State Security, the main security agency of the Soviet Union.
3. НКВД (NKVD)
'Народный комиссариат внутренних дел', or the People's Commissariat for Internal Affairs and its successors Cheka (ЧК) and OGPU (ОГПУ) are less known than the KGB, but in fact it was this structure that function as the defacto security service in charge of all the Bolshevik and Stalin repressions.
4. Комсомол (Komsomol)
The All-Union Leninist Young Communist League (Коммунистический союз молодежи) is the youth division of the Communist Party.
5. ГУЛАГ (Gulag)
The actual spelling is 'ГУЛаг', as it's shortened from 'Главное управление лагерей и мест заключения' or 'Main Directorate of Correctional Labor Camps'. The name of the penitentiary system later ended up replacing the names of the camps themselves.