It isn’t American history, so really shouldn’t be in this blog, but I thought you might enjoy this excellent podcast. I had heard this myth before, and I used to believe it. Not any more. This is a very interesting, rather long podcast, so if you don’t have time to sit back and enjoy the whole thing, go to the 12 minute 30 second spot and you can get the critical parts.
The myth says that Churchill learned by means of a decoded message that the Germans planned to obliterate Coventry, but did not warn the citizenry because it would have tipped off to the Germans that the English had broken their Enigma code.