This 1955 pamphlet from the United States Federal Civil Defense Administration
suggests how citizens might protect themselves from nuclear explosions and fall-out, including this advice:
"The best protection against atomic or
hydrogen bombs is—don't be there!
For major cities, this means pre-attack evacuation."
View the pamphlet (PDF).
I found it inserted among the pages of a dusty book.
The role of the United States Federal Civil Defense Administration is presently handled by the United States
Federal Emergency Management Agency (FEMA). FEMA was promenient in the news in 2005 as the U.S. federal agency
responsible for the response to Hurricane Katrina in New Orleans.
There are now about 25,000 nuclear weapons
said to be more than enough to plunge our entire planet into a 'nuclear winter'.2
Documentaries available on DVD:
NukeMap (shows affect of an exploding bomb at a location of your choice)