In fact, there were very few large bunkers in the USSR. Basically, they were shelters. They began to be built in the 1950s and were usually located under residential apartment buildings. But, I think, there were not so many of them to save the entire population of large cities. Some schools also had their own shelters. Many businesses also had their own shelters. There were several of them at large enterprises, and they provided jobs for all staff. Some strategically important enterprises also had underground workshops.

Today, most Soviet shelters have been repurposed, abandoned, or destroyed. Some time ago, the authorities made attempts to force enterprises to clean up their shelters, but this campaign has stalled and today, in fact, shelters are kept in order almost only by government agencies and some enterprises.