City Hall Subway Station
The Dark Manhattan's version of what (in our home universe) is the abandoned IRT station at Manhattan's City Hall: the area where Nita and Kit find the Eldest and the Book of Night with Moon.
This station started construction in 1900 as a showplace station for New York City's first subway project. It was in service from 1904 to 1945, at which time -- due to declining rider numbers caused by the greater convenience of other nearby stations -- it was closed. Its beautiful Guastivino arches and tilework languished for a long time in near-darkness, its skylights only recently cleansed of the blackout paint applied to them during World War II. Some of these skylights can still be glimpsed in the surface of the parking lot outside of City Hall.
Though alert subway riders can still catch a glimpse of the old station while riding a late-night number 6 train through the "turn-around" loop at the end of the line, no other physical access is allowed except by tours arranged through the nearby Transit Museum: so that online photo collections are the primary way to experience the station now. Some images, and more information about the station's history and architecture, can be found at its Wikipedia entry.
Probably the best of the independent online photo collections is at the New York Subway website; though it would also be a mistake to miss City Hall Station's entry at Joseph Brennan's labor-of-love website, Abandoned New York. This site also covers many other lost or strayed parts of New York's rapid transit system. (See also the "Forgotten New York" site here, and (ranging a little further afield) the links page at Modern Ruins. (SYWTBAW)
(See also: Subterranean ecologies: New York urban ecologies: Lexington Avenue local.)