Christopher Nolan's Batman out of the over-the-top camp that the mid-to-late 1990s movies left the character, it's unsurprising to see the collection of comic books used as a basis.
The likes of Year One, The Killing Joke, The Long Halloween, and Knightfall were prime examples of reference materials used as strong foundations. Though, while making sure to tell stories that felt new and inventive, there were several nods to classics like the aforementioned ones tastefully sprinkled throughout the trilogy for fans intimate with the comics to recognize.
Henri Ducard (Batman Begins)
Originally, Ra's al Ghul wasn't one of the teachers that trained Bruce Wayne while the latter was traveling around the world. In Batman Begins, Nolan incorporates two characters into one, with Henri Ducard becoming the "main" Ra's that serves as an antagonist for the movie (Liam Neeson).
The initial villain--played by Ken Watanabe--dies early on in the monastery and Ducard takes up the role, meaning that, in this universe, "Ra's al Ghul" is more of a mantle than it is a literal name like the comic version of the supervillain. This iteration of the character is a nod to Henri Ducard (first introduced in Detective Comics) in the comics, who does train Bruce, but in as an amoral detective--due to having worked both with Interpol and the criminal underworld, which led to the two having a strained relationship.
Calling For Backup (Batman Begins)
Nolan's trilogy opener obviously drew on Batman Begins shows Bruce's beginnings as a child to training abroad seeking the tools to find his purpose. The movie does well to weave scenes from the past in between the present, keeping an "origin story" movie engaging.
One scene in particular that paid homage closely to a scene in the comic was Batman's escape from Arkham. In order to distract the SWAT team from coming in to apprehend the vigilante and give Gordon time to exit with Rachel, Batman uses a sonar beacon to call on a swarm of bats. In Year One, he does the same thing when escaping a run-down building that the SWAT team was willing to bomb--with all the homeless citizens inside--to kill Batman.
Joker's Calling Card (Batman Begins)
While Frank Miller's Year One didn't get a direct sequel--rather, "indirect" ones through other comics like The Long Halloween--the ending of the comic left on a welcome cliffhanger teasing what's to come for Batman. With Gordon now having formed a budding alliance with this Caped Crusader, he waits by the Bat-signal internally talking about someone called Joker threatening to poison Gotham's reservoir.
Batman Begins brilliantly teases this in a similar adaptation, with Gordon and Batman by the signal after Ra's has been defeated, and the former suggesting that "escalation" has led to a similarly colorful figure causing problems around Gotham City, handing Batman a Joker playing card as sealed evidence.
Harvey Assaulted In Court (The Dark Knight)
In the vast catalog of Batman comics that are considered the best, Jeph Loeb's The Long Halloween is still frequently looked at as the character's best of the best. It's a thrilling noir crime-drama story that focuses on the Dark Knight as a detective--which is criminally underrated in movies--and also chronicles the tragic destruction of Harvey Dent and the rise of one of Batman's best supervillains in Two-Face.
In the comic, his downward spiral starts when one of the Maronis that Harvey is prosecuting throws acid from a small vial in his face in the middle of a trial. It eats away at half his face and brings out his psychological disorders in full force. Meanwhile, in The Dark Knight, this scene is somewhat recreated, but as a fake-out. Harvey is in the middle of a prosecution, but the Maroni thug pulls out a gun instead--only for it to be faulty and Harvey subdues him in self-defense.
The Return Of Batman (The Dark Knight Rises)
2012's The Dark Knight Rises uses the general premise of Miller's The Dark Knight Returns for inspiration, with the movie beginning with a Bruce Wayne retired from Batman for eight years. He's essentially become a hermit since willingly becoming Gotham City's scapegoat under false pretenses, but the rise of Bane encourages him to don the cape and cowl again.
However, this particular easter egg came in the scene of Batman's return to the city's shadows to chase down the surging supervillain. When two GD officers are in their car and in pursuit, Batman rides through on his Batpod, prompting the senior officer to recite a line from The Dark Knight Returns comic. He tells the young officer that he's in for a show, before the grand reveal of the Dark Knight's return.
Breaking The Batman (The Dark Knight Rises)
Of course, since Bane is the main antagonist of The Dark Knight Rises, Nolan had to recreate one of the most iconic Batman comic book s. Bane is a relatively "new" villain in Batman's rogues gallery when comparing the original appearances of the hero's other famous antagonists, but left an incredible impression from the start.
In the Knightfall arc, Bane breaks Batman's villains out of Arkham Asylum en mass knowing that the vigilante would run his body and mind ragged stopping them all with almost no rest. Once at his weakest, Bane infiltrates the cave to break the Bat, temporarily taking him out of commission. It's similar in Rises, with the first fight between the two taking place right under Wayne Enterprises R&D department and Bane finishing him by "breaking" him physically and in spirit.
