Churchill Downs is one of the most famous racetracks in the world, home to the Kentucky Derby — the first leg of horse racing's Triple Crown, run on the first Saturday of May every year since 1875. The twin spires above the grandstand are one of the most recognisable silhouettes in American sport, and during Derby week the entire city of Louisville transforms: hotel rates triple, the stands fill with enormous hats, and the mint juleps flow in extraordinary quantities.
Outside of Derby season, Churchill Downs is still worth a visit. The Kentucky Derby Museum on the grounds does an excellent job of explaining the race's history and the culture around it. Live racing continues through most of spring and fall, and a general-admission ticket gets you close to the track and the horses. The paddock area, where horses are saddled before each race, is one of the best places to watch.