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.