That's the supposed address for the residence of Sherlock Holmes. One of the PBS channels had a Sherlock Holmes movie on today -- I missed most of it, and picked it up just the very end.
My father loved Sherlock Holmes. He was keen on reading the books by Sir Arthur Conan Doyle (I seem to recall that he had several of those books, but I don't know what happened to them). I, too, thoroughly enjoyed watching the movies -- The Adventures of Sherlock Holmes -- on TV with my father. The world stopped whenever there was a Sherlock Holmes adventure on the tube.
Daddy would laugh and go tsk tsk and try to solve the mystery before Sherlock did. My father especially loved Watson, played by Nigel Bruce, and usually called him "the poor guy" in his falsetto voice, whenever Watson got in trouble. Sherlock, who could do no wrong, was portrayed by Basil Rathbone.
I know there are newer versions of the Sherlock Holmes mysteries, but there are none so good as the oldies we watched on TV in the 50s and 60s (late night movies). If they are in the TV programming I find them irresitable and will stop what I'm doing to watch Mr. Holmes solve the mystery -- assuming I find out about the showing of the film in a timely manner. :)