I was walking back to my hotel in Chicago when I passed this impressive buidling. I wasn't sure if it was open to the public but nobody stopped me from entering. The huge glass atrium was just immense. There was a food court downstairs and office space upstairs. It seems that the state of Illinois owns and occupies the entire facility.
I read that the building is very expensive to heat and cool since double pane windows were not installed as a "cost saving" measure.
Building security guards carefully watched me setup my tripod and take these shots but never said a word. Nor did any of the city workers that were constantly walking past me.
While in Chicago I found it interesting that unlike Californians, people there seem to totally ignore photographers indoors or out.