The Dark Knight is one of the greatest comic book movies of all time, ranked among the popcorn cinema elite in fan polls as one of the best movies ever. The penultimate chapter of Christopher Nolan's Dark Knight trilogy saw Christian Bale's Batman go up against the Joker, portrayed with haunting villainy by the late Heath Ledger, who won a posthumous Oscar for the role. Ledger's commitment to the character is the stuff of legend. But there were plenty of other cool facts behind the scenes, as well.

10 Katie Holmes skipped the sequel to make a terrible comedy.

Memento filmmaker Christopher Nolan rescued the World's Greatest Detective from the train wreck of glossy camp that was Joel Schumacher's Batman and Robin with 2005's Batman Begins, a serious minded reboot adored by fans and critics. Katie Holmes co-starred as Bruce Wayne love interest Rachel Dawes, but the Dawson's Creek actress passed on making the sequel, opting instead to join Diane Keaton and Queen Latifah in the comedy Mad Money, which bombed with audiences and critics.

9 Four A-listers were considered to replace Katie Holmes.

Katie's fellow WB Network veteran Sarah Michelle Gellar, star of the long-running genre series Buffy the Vampire Slayer, was among the actresses considered to play Rachel in The Dark Knight. Nolan reportedly also contemplated casting Isla Fisher, Emily Blunt, and Rachel McAdams before hiring Maggie Gyllenhaal.

8 At least five A-listers were considered for Two-Face.

The Joker of course isn't the only villain in The Dark Knight, which combines noir detective themes and post-9/11 dread with several comic based concepts, including elements of the storyline played out in Jeph Loeb and Tim Sale's Batman: The Long Halloween. Aaron Eckhart delivered a memorable performance as Harvey "Two-Face" Dent, a character played by Billy Dee Williams in Tim Burton's Batman and Tommy Lee Jones in one of its sequels, Batman Forever. Before Eckhart was given the job as Gotham's White Knight turned conflicted avenger, producers looked at Hugh Jackman, Ryan Phillippe, Mark Ruffalo, Matt Damon, and Liev Schreiber.

7 Heath Ledger was the only actor considered for The Joker.

Nolan has famously stated that Heath Ledger was the only actor he ever considered for The Joker. Onetime Joker Jack Nicholson complained that he wasn't asked back and a number of actors publicly expressed interest in the role, including Steve Carell, future Avenger Paul Bettany, and the late Robin Williams, who had starred opposite Al Pacino in Nolan's Insomnia. Ledger was chosen as Nolan's Clown Prince of Crime before the script was even finished. The rest, as they say, is history.

6 Christopher Nolan encouraged the Batman voice.

The voice Christian Bale uses in The Dark Knight trilogy to differentiate between Bruce Wayne and the Caped Crusader became a defining characteristic, often parodied, sort of imitated by Ben Affleck in the DCEU, and absolutely an inspiration for Will Arnett's voice performance in The LEGO Movie and its subsequent spinoff, The LEGO Batman Movie. In interviews, Bale explained that he came up with the voice during his audition for Batman Begins, where incidentally, he wore Val Kilmer's suit from Batman Forever. He thought Bruce Wayne should make a beast of himself when he dresses up in the suit; after the fact, he was worried that the voice had cost him the role. But not only did Nolan give him the gig, but he reportedly encouraged the Batman voice, including its modified sound in The Dark Knight.

5 Christian Bale actually stood on those high rise ledges.

Christian Bale could have used a stunt double, but he chose to stand on a ledge of the 110-story Sears Tower in Chicago, which stood in for a Gotham high rise. He did the same thing for similar scenes in Hong Kong. "How often do you get a chance to do that in a Batman costume? I'm not letting anybody else do that," he said in a 2008 interview with The Early Show on CBS. "The thing that was kind of disturbing but enjoyable was how comfortable I felt," he added. "It literally took 30 seconds."

4 Christian Bale did not ride the Batpod.

That Batpod was apparently way harder to operate than it looks. "It was deemed too dangerous," Bale said in an interview at the time. "They needed me in one piece to finish the damn movie." The actual prop was expected to fetch between $80,000 and $110,000 when it was auctioned off in 2016. It ended up selling for three times that.

3 Heath Ledger wanted Batman to hit him for real.

In October 2017, Joe McCabe published the book 100 Things Batman Fans Should Know & Do Before They Die, which included a collection of newly unearthed interviews the pop culture reporter had conducted around the time of the film's release, as well as an interview done with Ledger a couple of months before his death. Bale says their first scene together was the Joker interrogation scene. "I was saying, 'You know what, I really don't need to actually hit you,'" he recounted. "And he's going, 'Go on. Go on. Go on...'" As Bale put it so well: "his commitment was total."

2 There is only one Dark Knight deleted scene.

Heath Ledger passed away in January 2008. His work was finished on The Dark Knight and there isn't much else to see that isn't out there. Nolan is famously efficient about what he spends time shooting, with little to nothing left over in terms of deleted scenes. There is only one "extra" scene from The Dark Knight that we know about. It's the Joker escaping in a getaway car, just after storming Bruce Wayne's penthouse. A production still is the only evidence of this scene we've seen.

1 The Dark Knight includes a nod to Heath Ledger's daughter.

In the scene where the Joker visits Two-Face in the hospital, the nametag on his nurse's uniform reads, "Matilda." It's a tribute to Ledger's daughter with actress Michelle Williams. Matilda was just two years old at the time of her father's death.