WTC Area / Eyes
There's a lot of nice mosaic tilework throughout the NY subway system. Its been there since the system opened in 1904.
Much of the tilework was allowed to fall into disrepair up through the 1960s and 1970s. Now, a lot of the old tilework has been repaired, and there is some pleasant new tilework created.
Just north of the World Trade Center site, under Church Street, there is a five block or so underground passage that runs parallel to the entrances to the E,1, 2, 3, A and C trains and the closely intersecting Chambers Street / World Trade Center / Park Place stations. This passage is in very nice order, and it has mosaic eyes all from one end to the other. The eyes are cool.