Music has that ability to be a magical thing, and I was like, maybe music is the vehicle that transports us to that other world.

The problem is, when you're making an animated movie, the studio has an illusion in their minds - and it's really not true - that because it's a drawing, it can be changed at any time.

People always come up to me now and say, 'Watchmen' is the best superhero movie ever made.' I'm always saying 'That's super cool. That's nice of you to say.' But it happens now, more and more and more than it did when it first came out.

The thing about 'Dark Knight' is its objective is to set Batman into your world, so that you can imagine the moral dilemmas he faces are exactly parallel to moral dilemmas that you would face in this world, today, if you were out there fighting crime dressed like a bat.

We can deny angels exist, convince ourselves they can't be real. But they show up anyway, at strange places and at strange times. They can speak through any character we can imagine. They'll shout through demons if they have to. Daring us, challenging us to fight.

I'd say the purest experience for the movie is not to have read the book because I think when you've read the book you're just ticking off boxes. I think that after you see the movie, reading the book is a cool thing. I always say the movie's not meant to replace the book. That's ridiculous. I'm a huge fan of the book.

I think up to this point, it's been difficult to suggest a world where Batman and Superman and Wonder Woman and others could exist in the same universe. That was one of the things I really wanted to try and get at. Not to mention, the amazing opportunity to bring those characters and have those characters tell an important story, their own story, within the confines of a film.