simko:

Photograph of the secret City Hall subway station by John-Paul Palescandolo…

The City Hall Station on the Interborough Rapid Transit (IRT) line opened in 1904 as a showpiece for the new subway system. Unlike the rest of the line, City Hall featured tall tile arches, brass fixtures, and skylights that ran along the entire curve of the station.

The station was closed on December 31, 1945. The skylights were covered over and the station was boarded up. Although it would spend the next few decades closed to the public, the tracks were still used as the turnaround point for the IRT 6 after its final Brooklyn Bridge stop. So while the station was lost to the ages, it was not forgotten.

About a decade ago City Hall Station went through restoration. The idea was that it could serve as a transit museum. Unfortunately there were security concerns about this before September 11, 2001, and after those events, plans to permanently re-open City Hall Station would never happen.

But today there still is a way to see this wonder of the New York underground. The IRT 6 used to make all passengers leave the train at the Brooklyn Bridge stop, but not any longer. Those with a little extra time can stay on the train and view the City Hall Station as it is used as a turnaround. This is a little forgotten piece of New York that makes the city seem a little more intimate. (via)

Thanks for the hint, Ashley.