3. 76th Street Subway Station in Queens

The New York Times calls this the “Roswell” for “devoted subway buffs.” Its existence is hotly debated and the Times writes that “If it exists, in fact, it is nothing more than a dark four-track IND subway station with blue tiles, on the A line near Ozone Park, Queens.” And if it exists, it was part of plan to extend the A line to 229th Street in Cambria Heights, one of many proposed subway lines that never came to be. According to Joseph Brennan of Abandoned Stations, the station did exist and was in operation for less than a month in 1948. But even then, officials were denying its existence but unions at the time suspected cover up of non-union work.

Brennan contends that the station is still there, but today like in 1948, the official stance is that the station doesn’t exist. The tunnel to the station was sealed off in 1952. Brennan has maps and photographs showing the station’s existence, including one of a train at the platform and one of a subway board at Euclid Station, provided accidentally by the Transit Authority for the book Under the Sidewalks of New York.
But all this may be part of an elaborate April Fool’s Joke (not by us)–see the comment below from Benjamin Kabak of Second Avenue Sagas.