Talking to the Chicago Sun-Times, Transformers 3 director Michael Bay revealed why they are shooting in Chicago so much until the end of August. We're going to label the following as a spoiler, though we do have a note about it below the text:
Though Bay keeps his "Transformers 3" story line close to the vest, he did reveal the Chicago footage "is at the very end of the movie and the city is under alien attack, so it's very critical and important to the film's climax."
"Something very bad has happened to America -- and this is at the very end of the movie."
While it may sound like a big spoiler, it doesn't sound too different from the final scenes of the first two movies in which the Autobots and humans had to fight the Decepticons in a specific location. How they get in that situation is anyone's guess right now.
Transformers 3, starring Shia LaBeouf, Rosie Huntington-Whiteley, Josh Duhamel, Tyrese Gibson, Kevin Dunn, Julie White, Frances McDormand, John Malkovich, Ken Jeong, Patrick Dempsey, Alan Tudyk and John Turturro, hits 3D and 2D theaters on July 1, 2011.