Beginning in the 1950s, American and Soviet scientists embarked on a perilous race to see who could build and detonate the world’s largest bomb. The results exceeded all expectations about how big a bomb could be built.
I remember films like this. Of course, being a little younger than this film, the scare was more hydrogen bombs. My grade school years were in the shadow of the Cuban missile crisis. By that time, thermonuclear weapons made the idea of Duck and Cover kind of silly.