A race fan displays her hat before the 134th running of the Kentucky Derby horse race at Churchill Downs in Louisville, Kentucky, May 3, 2008.

Kentucky Derby is one of the classic US Thoroughbred horse races. It was established in 1875 and run annually on the first Saturday in May at Churchill Downs track in Louisville, Ky. With the Preakness and the Belmont Stakes, it makes up US racing's coveted Triple Crown. The field is limited to three-year-olds. The track distance is 1.25 mi (2,000 m).