The red metal borders surround old mosaics, steel work, even rivets and wiring, as well as six large pieces of the original 1904 wall from when the station was built.
If you have time to make it above ground to Union Square Park, head to the north side, and see a memorial that may upset members of the Turkish government.
Planted in April of 1985, the row of trees on the north end of the plaza are to commemorate the 1.5 million Armenian lives lost in the genocide of 1915 to 1923. On the northeast corner - where the trees end - there is also a plaque, which was then installed by the soon-gone Armenian population of the Murray Hill area (once called "Little Armenia").
Now, look south, and you can't miss Kristin Jones and Andrew Ginzel's bizarre artwork / timepiece, Metronome.
Built from February to October of 1999, the artists released a statement that the piece was to be an "investigation into the nature of time".
The work consists of "The Passage", the most eastern portion, which displays the time in a 24-hour format through 15 LED digits. The time below reads: "152047861123908", it means that the time is 15:20 (3:20 PM) and 47.86 seconds, and that there are 8 hours, 39 minutes, and 12 seconds left in the day.
There is also the much more esoteric center triptych, consisting of "The Relic" (a bronze hand), "The Infinity" (a circular wave pattern), and "The Source" (a golden emanation from a black hole, which pours out white steam at noon and midnight).
The third, seemingly-untitled section, was not photographed, as it's simply a rotating sphere near the corner of a large grid of metal.
After seeing what the artist themselves call "the most unloved piece of public art in the city", and you are still up for more in the park, there is a nice bronze statue of Mohandas Gandhi somewhere in the southwest section. It was installed on the 117th birthday (1986) of India's champion of nonviolent protest, and placed there by the Gandhi Memorial International Foundation.