The Gerald Ratner Athletics Center (colloquially, the Rat) is a $51 million athletics facility within the University of Chicago campus in the Hyde Park community area on the South Side of Chicago, Illinois in the United States. The building was named after University of Chicago alumnus, Gerald Ratner. The architect of this suspension structure that is supported by masts, cables and counterweights was César Pelli, who is best known as the architect of the Petronas Towers.
The Ratner Athletics Center was approved for use in September 2003. The facility includes, among other things: a competition gymnasium, a multilevel fitness facility, an Olympic-sized swimming pool, a multipurpose dance studio, meeting room space, and athletic department offices. It serves as home to several of the university's athletic teams and has hosted numerous National Collegiate Athletic Association Division III regional and University Athletic Association conference championship events.