Way down the street there's a lad in his place

Here's a floorplan of Sherlock Holmes' apartment at 221B Baker Street.

I've always been fascinated by the feel of the place. It's been represented on film and television so many times (and this is far from the first time anyone has ever made a floorplan).

There are always differences. Sometimes it is ornate and dark with lots of velvet curtains. Other times bare and bright with yellowing plaster walls. But it always seems the same. It always seems to be right somehow.

Is it familiar because I find it so interesting, or do I find it interesting because it seems so familiar?

And in this one - Those staircases are way too steep. You won't pass code with those things.