As I was researching something from that article, I ran into an article entitled Mystery on Fifth Avenue. If you enjoy reading about decorative oddities or weird house quirks or just dream about the day you can have a house that contains hidden passages or some other random mysteries feature, check this article out. If you hate reading long articles, and are more of the movie watching type, it just so happens you are in luck. There is a movie in development as we speak.
Speaking of which, did any of you history lovers happen to watch the White Collar episode about the flag George Washington took over the Delaware. The nerdy part of me just loved that episode, even if it's quite clearly not historically accurate. And yes, the episode did happen to contain a secret passage. So perfect!