its large, panoramic windows and natural light with an glass table and reflective bulbs. A Randolph Street parking garage is where Batman captures Scarecrow and Batman impersonators. Christopher wanted several Rottweiler dogs in the scene but locating a dog-handler willing to simultaneously manage several dogs was difficult. A scene of Batman surveying the city from a rooftop edge was filmed atop Willis Tower, Chicago's tallest building. Stuntman Buster Reeves was due to double as Batman, but Bale persuaded the filmmakers to let him perform the scene himself. The thirteen weeks of filming in Chicago was estimated to have generated $45million for the city's economy and thousands of local jobs. Filming in England and Hong Kong Many interior locations for The Dark Knight were filmed on sets at Pinewood Studios, Buckinghamshire, and Cardington Airfield, Bedfordshire; these locations include the Bat Bunker, which took six weeks to build in a Cardington hangar. The Bat Bunker was based on 1960s Chicago building designs, and was integrated into existing concrete floor, and used the long, tall ceiling to create a broad perspective. The tall hangar was unsuitable for suspending the bunker roof, and an encompassing gantry was built to hold it and the lighting. After moving from Chicago in May, scenes filmed in the UK also include Criterion Restaurant, where Rachel, Dent, and Wayne share dinner, and a Gotham News scene that was filmed at the University of Westminster. The GCPD headquarters was rebuilt in the Farmiloe Building. During the interrogation scene, Ledger asked Bale to actually hit him, and although he declined, Ledger cracked and dented the walls by throwing himself around. After returning to England in the middle of September, scenes were filmed for the ferry, hospital, and Gotham Prewitt building interiors. By mid-October, interior and exterior scenes of Rachel being held hostage surrounded by barrels of gasoline were filmed at Battersea Power Station. To avoid damaging the power station, a listed building, a false wall was built in front of it and lined with explosives. Nearby residents contacted emergency services believing the explosion was a terrorist attack. Filming in England concluded at the end of October with a variety of green-screen shots for the truck-chase sequence, and shots of Rachel being thrown from a window were filmed on a set at Cardington. The final nine days of production took place in Hong Kong and included aerial footage from atop the International