For example, closed cities that hid the secrets of the Soviet Union could be called such. It is worth noting that even today the true purpose of some of them is still classified. But first things first.
And let’s start with Zagorsk-6, located near Sergiev Posad. Inside the city, built in the late 50s, housed a scientific center that dealt with biological and viral weapons, both defensive and offensive. Yes, in the USSR, as in other large countries, there were laboratories, whose activities were of a dual nature.