A couple of months later, Warner Bros. released its own comic-book movie about a traumatized, guilt-wracked billionaire in an armored costume. The tone of The Dark Knight is completely different from that of Iron Man. Christopher Nolan worked to keep things grounded and visceral, limiting his CGI and essentially telling a crime epic, just setting it in a city where Batman and The Joker exist. The Dark Knight was a sequel, but unlike Jon Favreau with Iron Man, Nolan wasn’t trying to set up further cinematic adventures. (When The Dark Knight became a cultural phenomenon, Warner essentially had to beg Nolan to make another Batman movie, and it’s clear from The Dark Knight Rises that he never quite figured out what that should even be.) The impact of Iron Man and The Dark Knight showing up so close to one another can’t be overstated. With those two movies, everything changed.

Superhero flicks had already been doing big business before The Dark Knight and Iron Man; the previous year, Spider-Man 3 had been the box-office champion. But The Dark Knight and Iron Man both moved with a crisp confidence that had been mostly missing from blockbuster cinema for a long time. They arrived after an era when multiplexes were choked with noisy half-cartoon bullshit like the Pirates Of The Caribbean sequels, and they raised standards. Most of the competing summer spectacles couldn’t keep up.

Consider the case of Indiana Jones And The Kingdom Of The Crystal Skull, the third-biggest hit at the 2008 box office. Crystal Skull showed up right in between Iron Man and The Dark Knight. Like those movies, it had a nine-figure budget and a built-in audience. People were excited for it. Crystal Skull does have a few truly entertaining action set-pieces, but it also has Shia LaBoeuf and stupid aliens and a climax that looks like pure CGI gunk. Where Pirates Of The Caribbean had started out as a fun variation on the classic Indiana Jones tone, the Indiana Jones franchise ended up as a dog-ugly Pirates clone. A whole lot of people paid to see Crystal Skull, and Iron Man only barely edged past it on the year-end box office chart. But Iron Man got people’s heads thinking about what might be arriving next. Crystal Skull mostly just bummed people out.

The Dark Knight, meanwhile, had a rare form of electricity; I can only remember a few movies in my lifetime that had people that excited. Three years earlier, Nolan had introduced the new iconography and visual language of his Batman in Batman Begins. That film was a decent-sized hit. It didn’t exactly become a part of the cultural vocabulary, but it did remove the stink of ’90s slime-green neon cheese that Joel Schumacher had put on the franchise. It reset things, with a Gotham City that looked something like an actual city and with a Batman who never, ever smirked.

As Bruce Wayne and as Batman, Christian Bale was haunted and obsessed, so driven in his quest to become a terrifying ninja folktale that he lost all sense of himself in the process. Batman Begins ended with a truly great tease. Batman’s sense of the theatrical had drawn imitators, and now somebody was out there robbing banks, leaving behind Joker cards as a signature. I can still remember the hum in that theater when Batman flipped over the card.

That was the reset. When he brings us back to Gotham City at the beginning of The Dark Knight, Nolan has made things even less stylized. Instead, an extremely recognizable Chicago plays the role of Gotham. In the opening scenes, we see that Joker at work, and it’s a sight to behold. The heist sequence that starts off The Dark Knight, clearly modeled on Heat, is terse, vivid filmmaking. The Joker cleans out a mob bank, kills his co-conspirators, and escapes the dusty rubble in an orderly line of big yellow schoolbuses. From the moment that Heath Ledger first pulls off his clown mask to reveal his scarred-up clown makeup, Batman becomes a supporting character in his own movie.

In December 2007, that bank-heist sequence ran before some IMAX screenings of I Am Legend, and people rightly flipped out about it. A month later, Heath Ledger died after taking the wrong combination of pills. Ledger’s death was an out-of-nowhere shocker. An actor who was already looking like one of his generation’s best left the earthly plane behind just as he was starting to reveal the true extent of what he could do. Hearing of Ledger’s death felt a lot like learning that Chadwick Boseman had passed away last year. It didn’t seem real, and his absence gave some mystical weight to The Dark Knight before it even came out.

At this point, it seems ridiculous to even talk about Heath Ledger’s Joker. What else can you say about it at this point? Since Ledger’s death, we’ve had two different movie Jokers—or three if you count Zach Galifianakis in The Lego Batman Movie, or four if you count Jared Leto’s Joker in Zack Snyder’s Justice League as being different from Jared Leto’s Joker in Suicide Squad. Last year, Joaquin Phoenix won an Oscar for his Joker, just as Ledger did posthumously. (At this point, only two characters in history have won Oscars for two different actors: the Joker and Don Vito Corleone.) And yet all these baby Jokers still labor in the shadow of what Ledger did with his turn as the character. Ledger’s Joker instantly became a cultural touchstone. After 13 years of memes and bad impressions, we should all be sick of him. And yet any time I watch The Dark Knight, I can still feel pulses of electricity whenever Ledger is on screen.

Ledger’s Joker isn’t a human being. He’s a mystical force, a destabilizing agent. He has no name and no background, and he tells different stories about his scars whenever anyone gives him the chance. He has nothing in his pocket but knives and lint. He likes stabbing people to death so that he can savor the little subtleties of emotion. He manages to nonchalantly fire a bazooka from a moving truck. He sets impossible chains of events into motion, and they all mysteriously seem to work out in his favor.

Nolan surrounds Ledger’s Joker and Bale’s Batman with an absurdly overqualified cast: Michael Caine, Gary Oldman, Morgan Freeman—all wizened Oscar winners, all given great little character moments even though they’re mostly there for exposition and background flavoring. Aaron Eckhart’s Harvey Dent gets a full tragic arc, starting off as the kind of incorruptible prosecutor who will punch out a courtroom gunman in the middle of a cross-examination and ending it as a half-melted monster driven mad enough by grief that he’ll force Jim Gordon to pick which kid he murders. Even in the roles that only get one or two scenes, Nolan makes sure to pack in people we’ll be happy to see: Eric Roberts, Michael Jai White, Anthony Michael Hall, Tiny Lister.

The Dark Knight moves like a machine, never lingering too long on anything, never giving anyone a chance to get bored or to register how little sense the story makes. Nolan’s hand-to-hand action filmmaking is as frustrating and chaotic as ever; the close-quarters fight scenes in last year’s Tenet might be the first truly effective ones that Nolan has ever staged. But the widescreen moments—the shots of Batman posing on rooftops, the bodies crashing through windows, the truck flip—are breathtaking. For me, The Dark Knight falls apart at the end, a victim of the cluttered and chaotic storytelling that would doom The Dark Knight Rises. But up until then, it’s a relentless blast.

The Dark Knight and Iron Man might’ve been the two biggest films of 2008, but the race between them was not a close one. At the domestic box office, The Dark Knight earned $534 million to Iron Man’s $319. Commercially, nothing was touching The Dark Knight. Nolan’s film became such a part of culture that its big quotes immediately became cliches. Other filmmakers took the wrong lessons, trying to tell pulpy tales with square-jawed stoicism. (Marvel, smartly, went in the opposite direction, jamming every movie with bright colors and quippy yammering.) But on that grand operatic scale, nobody else, including Nolan himself, has managed to fully recreate the feeling of immersion that he brought to The Dark Knight. It’s the movie where everything clicked. There have been bigger, more lucrative movies since The Dark Knight, but there hasn’t been anything that resonated in quite the same way.

Six months after The Dark Knight opened and shattered box-office records, the Academy nominated five films for Best Picture: The Curious Case Of Benjamin Button, Milk, Frost/Nixon, Slumdog Millionaire, and The Reader. A couple of those are good movies. A couple of them were hits, too. None of them had a cultural impact anywhere near the level of any random five-minute chunk of The Dark Knight. Quite frankly, none of those nominees are anywhere near as good as The Dark Knight, either. The popular outcry was swift and loud, and the Academy, faced with its own dwindling relevance, panicked and changed the rules. From the next year on, the Academy could nominate as many as 10 movies for Best Picture. These people did not want another Dark Knight to go by unrecognized again, and that, specifically, was why they altered the playing field. The Dark Knight literally changed the game.

The runner-up: There was another popular masterpiece in the summer of 2008. Pixar, after a historic run of success, put itself to the test with WALL-E, its beautiful little apocalyptic fable about a lonely robot on a garbage planet. WALL-E’s near-wordless first act is a beautiful little silent romantic comedy. Things change when the robots get to space and the humans come into the picture, but that part is great, too. (It also remains relevant, especially after so many of us just spent a year lolling around our houses and doing jack shit.) Up against stuff like Kung Fu Panda and Madagascar: Escape 2 Africa and Horton Hears A Who—all big hits—WALL-E works as kid-movie hijinks, and it proves that kid-movie hijinks can still be poetry.