So many of the Sherlock Holmes stories begin at the famous flat at 221b Baker Street in London, that we overlook one obvious fact. The address is so well-known, that we assume everyone knows where Baker Street is! Somehow I think that's a mistake - especially for those who have never been in London. Let me place Holmes residence more exactly. Baker Street runs from Regents Park to Hyde Park. The southern end, near the marble arch is the site of the United States Embassy, and so halfway between Regents Park and Hyde Park, we join Sherlock Holmes and Dr Watson at 221b Baker Street...