Governments and authorities like maps. They're a useful way of clearly saying this is mine, that is yours. They're also useful for saying where you can and more importantly, where you can't go. This is all too evident in a surprising map of where Russian visitors to the US were permitted to visit during the 1950s.

In the mid 1950s America and Russia were in the middle of the game of oneupmanship, with added nuclear weapons, that was the Cold War. Despite the uneasy detente between the two countries, if you were one of an elite group of Soviet citizens you were actually able to visit the United States. But not all of it. Large swathes of the US were closed to prospective Soviet tourists.

What makes this map interesting is not so much the slice of relatively recent world history that it portrays but more of the questions it poses. What were the criteria that were used to determine where a Cold War era Soviet visitor could and couldn't go?

You can make some educated guesses. It's not unreasonable to assume that major ports, coastlines, industrial areas and military and weapons areas were off limits. But that doesn't cover the full scope of the open and closed areas.

Over at BoingBoing, there's speculation that this was as much a tit-for-tat set of restrictions as it was a set of restrictions based on what the US Government didn't want Soviets to see. As Cold War era historian Audra Wolfe, the author of the Slate article on this map, notes

The main premise is 'strict reciprocity'. X% of Soviet coasts are off-limits, therefore X% of US coasts are off-limits, too.

Photo Credits: Rockefeller Archive Center, Item record: Rockefeller Family Archives (III) Record Group: 4 Nelson A. Rockefeller – Personal, Series: Washington D.C Files, Subseries: O.9 Special Assistant to the President Declassified Materials, 1954-1956, 1969 Box: 4 Folder 94.