New York City’s century-old subway system has a labyrinth’s worth of abandoned tunnels and stops. But the 76th Street station in Queens is by far the most mysterious. Why? Because the 76th Street station may not exist at all. According to the New York Times, the bricked-up stop “has been rumored to sit just east of the Euclid Avenue station, part of a grand, never-realized plan to continue the A line out to 229th Street.” Why that plan was scrapped, and if the station was ever built at all, remains…