Closed city

A closed city or town is a settlement where travel or residency restrictions are applied.

Historically, the construction of closed cities became increasingly common after the beginning of the Cold War, particularly in the Soviet Union. Since the dissolution of the Soviet Union in 1991, they remain widespread in Russia and some of the other post-Soviet countries. In modern Russia the closed cities are designated as "closed administrative–territorial formations" (ZATO; Russian: закрытые административно–территориальные образования [ЗАТО], PRON. zakrýtïe administratívno–territoriál'nïe obrazovániya).