The 1894 Romanesque Revival mansion of lumber tycoon David Whitney. The 42 room structure is made of South Dakota jasper, designed by Gordon W. Lloyd. Louis Comfort Tiffany stained and leaded glass windows throughout.
It reopened recently after a change in ownership. This house has always been maintained in a proper manner, and is nearly pristine. It functions as a fine dining restaurant.
Heres a photo from the Library of Congress of the David Whitney home the way it looked when he lived there back in the late 19th Century.
Basically, any building with turrets and hidden faces is as cool as all get-out.