Christopher Nolan, the director of the blockbuster "Batman" film franchise, said it was time for him to end the series as a trilogy and his up-and-coming "The Dark Knight Rises" will be his last Batman film.
"You could go on doing it forever, but it wouldn't be the right thing to do," Nolan told "Nightline" in an exlcusive interview. "The right thing to do is to know you've told the story you've set out to tell and that is very much the case with the end of this film."
"It's all really about building to this moment," he added. "I've been working on these films for about nine years now and we have a beginning, a middle and an end now."
Prior to "The Dark Knight Rises," which is out in theaters nationwide July 20, Nolan's "Batman Begins" (2005) and "The Dark Knight" (2008) enjoyed explosive worldwide success, leading up to "The Dark Knight Rises."
"I love Batman because we could all be Batman," Nolan said. "There's this sense of he's a human being whose pushes as far as he possible can and keeps pushing himself further and further."
The filmmaker had high praise for Christian Bale's portrayal of Batman, and said the actor brought "focus and discipline" to the role.
"Bruce Wayne is a very tortured angry guy who does a lot of pushups," Nolan said. "[And Bale] takes what he does very seriously, but he doesn't take himself too seriously. He is the first to acknowledge the inherent ridiculousness of what an actor has to do sometimes. But never will lose, never takes his eye off the ball."
Bale said being Batman opened many opportunities for him with other films that he didn't have before.
"It's meant a great deal in my life in how it's changed... my career," Bale said. "Nobody wanted to cast me for things. It's gotten me over that hurdle."
Nonetheless, Nolan said "we're done" with the franchise and Bale agreed that it was time to walk away.
"I'm certainly proud to have been involved in what Chris has achieved," he said. "I was never sure Chris was even going to do a third [film], so it seems -- leave when its complete... Chris is a really great storyteller. If he says that's it, that's it."
As they wrapped his final installment, Nolan said he went through a "series of emotional good byes" with the cast and crew.
"I remember saying good bye to Michael Caine [who plays Alfred] in the bat cave," Nolan said. "That was the last of his scenes that he shot. So it was very specific, like 'OK, we're never coming back here again.'"
Nolan has been praised for shrewdly revamping the "Batman" film franchise away from its cartoonish predecessors, which drew more on the "straight from the comic book pages" approach.
"Comic book movies have become too much about acknowledging the source material," Nolan said. "For me, it was saying, OK, I don't want to acknowledge the source material in the look and feel of the film, I want to make a real film. A film that tries the best it can to present an exciting and realistic world."
The last time the audience visited that world was with "The Dark Knight," a film that dove deep into the fears and horror of a post-9/11 world. But the film is perhaps better remembered for the late Heath Ledger's striking performance as the movie's villain, The Joker.
"[I] tried to construct the freedom for him to really be able to explore... to say, 'let's really play with this, let's really try and find the psychological reality of the character,'" Nolan said of directing Ledger in the role of The Joker. "Heath just had a ball with it. He had a blast. It was an incredible thing to be a part of? you never knew what his voice is going to do."
Ledger posthumously won an Oscar for Best Supporting Actor for the role.
In "The Dark Knight Rises," Nolan chose Bane, an unfeeling genius with venom in his veins, for his villain, played by actor Tom Hardy. The filmmaker said he chose Bane because he wanted an antagonist who would make viewers "fear for Batman's physical safety."
"What Bane provides is this incredibly frightening physicality," Nolan said. "He is a militaristic presence. He's a monster."
Bane exudes a different kind of evil than previous villains, Nolan said, but the character stays true to his attempt to make the audience have that "unsettled" feeling that the villain could be real.
"We didn't want to do any kind of watered-down version of what Heath has done as The Joker, which was such a seminal thing," he said. "I really wanted to do something completely different and something primarily physical."
But now that he has wrapped his Batman opus, Nolan said he doesn't have anything else in the works yet.
"I really have no idea what I am going to do after this, and I kind of enjoy it," the filmmaker said, laughing. "I'll get bored eventually and figure out what I want to do next because I do love making films, but for me it's always been about a story -- a story that hooks you."