A very Soviet phenomenon, but one still existing in modern Russia, although many cities are now "open". Known as ZATO (''zakrytye administrativno-territorial'nye obrazovaniia'') in Russian.

Appeared from the late 1940s onwards.

These are entire cities that foreigners cannot enter and Russians need a permit to live there, being subject to movement restrictions. Some were physically surrounded by barbed wire, with armed guards. They were referred to only by a postal-code and did not feature on Soviet maps. They were located in remote areas. These cities were usually there to serve the needs of defense industrial complexes or classified research institutes. Most of them were not large enough to be considered cities proper, more likely towns, but they were planned and built as full complexes of urban infrastructure, unlike naturally evolved Russian towns, which resemble overgrown wooden villages with a few apartment blocks thrown in. However, those closed cities that already existed as cities before the Revolution were true cities; none of these remains closed today.

Note that living there was not necessarily bad - it involved (and to a lesser extent, still involves) reasonably good and prestigious if secret work, lots of cool if sometimes dangerous stuff happening, and various privileges such as a temporary exemption of local businesses from taxes in the Nineties.

Other closed areas existed elsewhere in the WarsawPact, especially on the border between WestGermany and EastGermany.

42 are acknowledged to exist today in Russia, but c.15 more are believed to exist.

Some of them were or are:
* Severomorsk. Administrative base of the Russian Northern Fleet. Still closed.
* Gorky, now open and back as Nizhny Novgorod.
* Tryokhgorny. Still closed.
* Mirny, Arkhangelsk Oblast. Still closed, it is home to the Plesetsk Cosmodrome.
* Verkh-Neyvinsk, aka Sverdlovsk-44. Still closed.
* Snezhinsk, Chelyabinsk Oblast. A nuclear research center.
* Sverdlovsk, now Ekaterinburg. Not a proper closed city, but it was still practically closed to foreigners because of its status as an industrial center. It was not the only such borderline case.
* Mezhgorye, a closed city near Mount Yamantau that hosts some 17,000 residents that work on defence facilities around the mountain. It may be the home of the ''[[DoomsdayDevice Dead Hand]]'' or ''Perimeter'' semi-auto-second-strike nuclear launch system devised by the Russians, but is known to house nuclear labs and nuclear weapons development. Think of it as the Mt. Cheyenne analogue.
* Chelyabinsk, now open, a centre of nuclear weapons development and notorious for a [[FailsafeFailure nuclear accident]] in the 1950's that left significant parts of the area irradiated.
** The accident happened not in the city itself, but at the "Mayak" plant, a huge industrial complex responsible for much if the Soviet nuclear production, in the even ''more'' closed city of Ozyorsk, then known as Chelyabinsk-40, some 72 km from the Chelyabinsk proper. As both the plant and the city were classified at the time, the accident became known as Kyshtym disaster, after the closest "open" town.
* Vladivostok, main base of the Pacific Fleet. Now open.

In fiction:
* In ''Literature/DevilMayCare'' [[spoiler: Julius Gorner attempts to destroy Tryokhgorny, referred to by its postal name Zlatoust-36]].
* Possibly non-Russian example: [[VideoGame/HalfLife2 City 17]]. It is an Eastern European city, but it wasn't the humans that closed it.
* An episode of ''Series/{{Airwolf}}'', "Proof Through The Night", is set in Sverdlovsk.
* In ''TheSumOfAllFears'' movie, agent Cabbot speaks about the closed city called Arzamas (most probably referring to Arzamas-16, now Sarov).
* The game ''Gorky 17'' (a.k.a ''Odium'') takes place in the eponymous closed city (note the error in transcription, as there should be a dash between the name [Gorky is an actual city] and a number).
* [[DestroyAllHumans Destroy All Humans 2]] had a fictional one vaguely called "Tunguska". It played up all the stereotypes [[UpToEleven To Eleven.]]
* The "Ensk" Map in ''VideoGame/WorldOfTanks'' is based on a closed city layout.
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