The mornings were so cold in Santa Clarita that the crew had to have ice cubes on hand for the actors to suck on to keep their breath from showing.
The Baghdad interior house scenes were shot on the Mormon compound set of the HBO show "Big Love" while the show was on production hiatus. The production designers completely redesigned the set with authentic Middle Eastern furnishings, down to the light switches.
When the Humvee would not start as a result of the freezing temperatures in Santa Clarita, the entire crew, actors and all, got together to push the 8000lb Humvee up a hill into place for the first scene.
The army base scene, complete with rows of military vehicles and trucks, was actually shot in the maintenance parking lot of a prop vehicle rental depot. The shots were carefully selected and composed to hide the surroundings.
The most complex shot of the film of a Baghdad exterior scene featuring street merchants and fruit-sellers and multiple picture vehicles had to be cut from the final film due to time constraints.