Who played the lead female part in "The Dark Knight" from 2008?

Explanation

The Batman franchise has a long history. It began with comic books, but Batman was made into a movie as early as 1966 with Adam West starring as the title character. This spawned a TV-series, but the series did not have a comeback until Tim Burton's 1989 movie was released. Subsequently, there were a few more movies in the 1990s, such as Joel Schumacher's "Batman Forever" and "Batman & Robin". Recently, Christopher Noland has revitalized the franchise with his "Batman Begins", "The Dark Knight" and "The Dark Knight Rises". Christian Bale has starred in these movies so far, while a number of different actresses have played the lead female role, e.g. Maggie Gyllenhaal in "The Dark Knight".