After the World War 2, during the period of Cold War, thousands of shelters were built in different regions of the USSR. Now some of them abandoned, and some are repairing and well secured. One of the abandoned big shelters in the region of Kaliningrad, that can accommodate more than 1000 people in time region is on the pics below.
There are three entrances like this. All of them have two sealed doors.
The doors are wide because they were designed for large amount of people.
A gas mask.
The calendar is on 2008