The University of Illinois at Urbana–Champaign (also known as U of I, Illinois, or colloquially as the University of Illinois or UIUC) is a public research university in the U.S. state of Illinois. Founded in 1867 as a land-grant institution in the twin cities of Champaign and Urbana, it is the flagship campus of the University of Illinois system and a founding member of the Big Ten Conference. 

The University of Illinois at Urbana–Champaign is a member of the Association of American Universities and is classified as a R1 Doctoral Research University under the Carnegie Classification of Institutions of Higher Education, which denotes the highest research activity. In fiscal year 2015, total research expenditures at Illinois totaled $640 million. The campus library system possesses the second-largest university library in the United States after Harvard University. The university also hosts the National Center for Supercomputing Applications (NCSA) and is home to the fastest supercomputer on a university campus. 

The university comprises 17 colleges that offer more than 150 programs of study. The university holds 651 buildings on and its annual operating budget in 2016 was over $2 billion. The University of Illinois at Urbana–Champaign also operates a Research Park home to innovation centers for multinational corporations and publicly traded firms including Abbott, Caterpillar, Capital One, State Farm, and Yahoo, among others.
Within how many structures?
The university holds 651 buildings