Thunder Over Louisville is an airshow and pyrotechnic display that takes place during the opening of the Kentucky Derby Festival, in mid-April. The tradition of fireworks on Derby Day—the most famous horse race of Louisville—dates back to 1991. Since then the fireworks have taken place in the same location over the Ohio River. They are launched from large barges in the area of the George Rogers Clark Memorial Bridge and from the bridge itself. In 1992, the airshow was added to the program. Every year, the event attracts about 625,000 attendees to the Louisville Waterfront Park. Crowds gather in Louisville and across the Ohio River in Clarksville and Jeffersonville, Indiana.
Thunder Over Louisville generally starts at about 3 p.m. with an air show that features U.S. Army Golden Knights, CF-18: 401 Tactical Fighter Squadron Cold Lake, Royal Canadian Air Force, KC Flight: RV-4 Color Smoke trails, and other participants. After dark, at 9:30 p.m., the culmination of the show occurs. The pyrotechnic spectacular, accompanied by a synchronized soundtrack leaves hundreds of thousands in awe.
Thunder Over Louisville is included in the top 5 largest airshows in the United States. In 2007 it had a record crowd of 850,000. In addition to the excitement in the sky, it features lots of attractions on the ground: several live entertainment stages, the Military Interactive Display Area, Thunder FoodFest, and the Kid’s Play Areas on the Great Lawn of the Waterfront Park.