The City Hall subway station

It's also known as City Hall Loop,was the original southern terminal station of the first line of the New York City Subway, built by the Interborough Rapid Transit Company (IRT), named the "Manhattan Main Line", and now part of the IRT Lexington Avenue Line. Opened on October 27, 1904, this station underneath the public area in front of City Hall was designed to be the showpiece of the new subway. The station was designed by Rafael Guastavino.  Passenger service was discontinued on December 31, 1945, making it a ghost station, although the station is still used as a turning loop for 6 trains, and if you want see that, you have to stay in 6 train and wait inside while the train turn loop.