This video requires something of a time commitment, but it's worth it. This guy goes into a subway tunnel and we get to see this magnificent old, unused gorgeously tiled (and, just for us, very well lit) station. After that, he sets off on another tangent, but honestly I haven't watched that part yet. I think it has to do with going into the Canal (ie Canal Street).
Thanks to Danny (Dan, no sorry you are Danny), for the link.