The set of the Batman BEGINS sequel in Chicago, Illinois was brought to a standstill yesterday (24Apr07) after a fire broke out. The blaze broke out on the roof of a vacant post office building, which was being prepared for a scene in The Dark Knight. The city's fire department responded quickly to the fire, which is believed to have started in the building's ventilation system. As WENN went to press, it was unclear whether the filming was responsible for the fire. No one was injured. The post office building was being used as Gotham National Bank in the film.