Since Chicago became Gotham City in "Batman Begins," returning there for "The Dark Knight" made perfect sense. Not only was the city accommodating to the production, "It has an enormous amount of wonderful architecture in a very small area, a lot of modernism plus turn of the century classic buildings, so when you photograph it you get a bit of everything," notes production designer Nathan Crowley. Bruce Wayne/Batman's home, Wayne Manor, burned down in "Batman Begins," "So it was a great excuse to put everything in town and with that came a modernist city, with clean lines, to make you feel that it's a more hard-edged place."
Taking over downtown Chicago for 12 weeks was made easier by cooperation from city agencies, but was a difficult proposition. "We were having to close down streets," points out producer Emma Thomas. "They let us take over their financial district at night as long as we were safe, and they made sure that we were," adds producer Charles Roven, though he reveals one mishap involving the Bat-pod cycle.
"It came out of an alley onto the street and created a huge sonic boom that blew out a bunch of windows in a building. That was not planned. But we mobilized glaziers and within 24 hours we had fixed every window."
Careful planning avoided potential disaster in flipping that semi truck on La Salle Street, which Crowley describes as "a narrow canyon of historic buildings. Then you have city sewers and electric cabling below the road, so there were a lot of logistics. You plan, you test and you do it once."
Similarly, there was no room for error in a scene where The Joker blows up a hospital. A vacant building in Cicero, Ill., that was slated to be demolished was the perfect stand-in, once it was dressed with the proper facade and signage.
The production used another vacant building, a former post office, for the opening bank robbery sequence, but the film also took over spaces currently in use. "The boardroom was an existing floor in the IBM building that we refitted. We wanted to have a real view outside the window," Crowley explains. "You're dealing with building management so there's a lot of negotiation."
That was also the case in Hong Kong, where, according to Roven, it took nine months to get the permits needed to shoot there. "What we were doing there was complicated, and we were doing it in very highly populated centers. A lot of it had to do with big action set pieces with a lot of vehicles," he explains.
Twice during production, filming moved to locations in England, including Cardington, Bedford, Pinewood and Leavesden Studios, and London. "There's an enormous old airship hangar that the British government used to test concrete and steel, and there's two existing buildings within it," notes Crowley. For a climactic high-rise sequence, "We intercut footage shot there with the exterior of a building under construction in Chicago."
Despite all the outdoor shooting in that city, weather didn't prove to be an obstacle, according to the producers. "We were very lucky that we were there in the summer. It was hot during the day, but we were shooting at night," says Thomas. "The only problem with that was the nights were short," adds Roven. "We had to wait till almost 9:00 and it was starting to get light by four in the morning."
Keep reading to learn more behind the scenes secrets about the special effects in "The Dark Knight."