There's so much written about every nook and cranny of New York City that it seems like everything is known. Here is a list of unsolved mysteries in the city.
Remnants of the fabled Atlantic Avenue tunnel, the first subway tunnel in the world, are now accessible through a new speakeasy, Le Boudoir, in Brooklyn Heights
Far lesser known in NYC are the obscure tunnels–often running from building to buildings or through lesser documented parts of the city. Here are 7 secret ones