Napoleon Letter Breaks Estimates

An interesting letter was recently auctioned: written in code, and signed by Napoleon, it was sent when the French Emperor was pondering a retreat when his Russian campaign in 1812 was failing. What's intrigued people, and the chief reason it far exceeded the estimate and sold for nearly a quarter of a million dollars, is that in it Napoleon promises to blow up the Kremlin in Moscow. In the end, of course, the Kremlin far outlived Napoleon's empire (and a few Russian ones besides.)