Even today, Zarechny is full of out-of-bounds areas, most notably Rosatom, a state-owned corporation that manufactures parts for nuclear weapons; photography is banned there. It was only in 1986 that Russians were officially told of the closed cities in their country.

Visitors to closed cities had to be invited by residents, and even then it wasn't guaranteed they would be allowed a permit to enter. Zarechny’s 62,000 inhabitants are now free to come and go, but still live encircled by barbed wire fence.

Closed cities were nicknamed “post boxes” because mail for the inhabitants would have to be sent to special post boxes in nearby towns rather than delivered directly. Though closed cities like Zarechny have gradually been opening up, dozens of others remain disconnected from the outside world. Some residents of Russia's closed cities says they prefer to live an more isolated life. Others are waiting for an opportunity to leave.

According to theguardian.com