Blue Cross and Blue Shield of Illinois Tower is a curiosity among Chicago high-rises due to its construction in two phases over two separate decades. The original 30-story building was completed in 1997 to satisfy the health insurance company’s immediate space needs. However, it was also engineered to allow for future upward growth. From 2007 to 2010, 24 stories were added, seamlessly extending the building to 54 floors in height. The tower's extensive use of glass, inside and out, creates stunning atrium spaces and provides outstanding views of Grant Park and Lakeshore East.