While there is nothing particularly special about this restroom in terms of appearance, convenience or features, it's the location that makes it so unique. This tiny bathroom -- and many others in the State Tower Building -- is located in the stairwell. As seen in the second picture below, the door opens directly off of the stairwell itself. Many of the restroom doors are locked, and presumably can only be accessed by people with offices on the corresponding floors. The 16th floor women's room was open, though, allowing me a peek inside. (Note: I did not realize it was a women's room until after I was inside, so please don't think of me as too much of a creep.)
Again, this is fairly standard stuff. But the view from the large window is absolutely spectacular, and quite unlike any you will find from most bathrooms.