The Maginot Line.
But was it a provocative act or a future defensive one?
Of course if it was provocative, the French did not take into account that the machines of war would change so much in the ensuing 20 years.
In fact, that has always amazed me. That airplanes could go from canvass and balsa wood to the B29 in so short a time.
Once we set technology lose, we have no way to call it back.
