44 West 73rd
As late as the 1990s, the Upper West Side still had a number of abandoned townhouses pockmarking its blocks, 19th century relics that somehow survived of the dark post-WWII history in American cities. Soaring real estate values resulted in the renovation or replacement of most of them, but this one still remained as late as 2013. Tied up in an estate or some other confusing chain of ownership, perhaps.
Next: 455 Central Park West