In 1995, nobody would know the lasting impact of Michael Mann’s grandiose sweeping crime drama, Heat would have on pop culture and audiences. Originally billed as the showdown between Al Pacino as Detective Vincent Hanna and Robert DeNiro as master thief Neil McCauley, there was more substance to the historical moment than expected.

The movie isn’t just a character study of both men and their respective crews, it’s a blueprint for how to do an action film, a heist film, and a drama film, all in one. It’s the movie Christopher Nolan cited as a direct influence on The Dark Knight which, over ten years later, is still the definitive Bat-flick. After almost 25 years, Heat is still the decisive crime-drama. Without further delay, here are 10 things you didn’t know about Heat.

Keanu Reeves Was Almost Chris Shiherlis

Several years before The Matrix and 20 years before John Wick, Keanu Reeves was still mostly known for saying “Whoa” and not much else. But in 1994 and thanks to Speed, that image was beginning to change.

With Val Kilmer off in a Batsuit somewhere in Batman Forever, Mann wasn’t sure Kilmer could juggle both roles and almost cast Reeves instead. Considering his dedication to plenty of action roles like this, Reeves would have been just as, if not nearly, as good as Chris.

Danny Trejo Is An Ex-Con

As most movie fans know, method actors like Robert DeNiro get deep into the roles their playing. They do extensive research for whichever character they’re playing. For Heat, several actors spent some time wandering around the halls of San Quentin Penitentiary to get a feel for how ex-cons would walk and talk.

But one member of the crew already knew, because he had been in and out of prison in his youth and had served time in San Quentin. That actor was Danny Trejo, who did time for petty crimes before becoming an actor.

L.A. Takedown

Michael Mann was no stranger to TV, having been the executive producer of Miami Vice. Years prior to directing Heat, he wrote a TV pilot called L.A. Takedown. It was later reworked into a TV movie that starred Scott Plank as Det. Hanna, who was hunting down the professional criminal Patrick McLaren.

At the time of its release, L.A. Takedown received mixed to negative reviews and was mostly forgotten. Obviously, Mann reworked this pilot into what Heat would later become. L.A. Takedown has developed a cult following as well, thanks to this film.

Heat Is Based On A True Story

While the words “Bases On Actual Events” do appear in the final cut, Heat is in fact inspired by the real-life career criminal Neil McCauley and the Detective tracking him - Chuck Adamson. The two rivals even met for coffee once before McCauley’s final heist.

Adamson became a producer and technical advisor for the movie inspired by one of his career’s most notable cases. McCauley’s fence, Eddie Bunker, was also based on the real person. Eddie was played by Jon Voigt in the movie.

Heat Is A Marine Training Video

Heat leads up a massive robbery and subsequent shootout on the streets of Los Angeles. It’s one of the most harrowing action sequences ever shot on film. If it seems real, that’s because it is - no CGI was used, and Mann placed microphones all over to capture the noise.

The actors underwent extensive training for the firefight. The police use semi-automatic settings to protect the civilians while the the criminals are on full automatic, only worrying about their own safety. This scene has been shown to some Marine classes to teach proper cover fire, return fire, and reloading techniques.

The 1997 North Hollywood Robbery

Not only was Christopher Nolan influenced by Heat, but several shootout-style robberies were also influenced by the film. Most famously, two yahoos in 1997 got it in their heads that they’d be able to pull off the same exact robbery.

The North Hollywood Shootout was and still is the deadliest robbery of its kind - both criminals were killed, while 11 police officers and 7 civilians sustained injuries. The crooks barely got away in the film, how these two real-life criminals thought they’d get away is just ridiculous.

30 Seconds To Walk Away

Neil McCauley has lived by a code. In his own words: “Don’t let yourself get attached to anything you are not willing to walk out on in 30 seconds flat if you feel the heat around the corner.”

The film, besides being named after this quote, takes full advantage of that time. When Neil and Eady spot Hanna at the airport, Neil takes a few seconds to assess the situation. He takes exactly 30 seconds to contemplate leaving Eady or not. She’s clearly heartbroken at first, but Neil leaving her, kept her safe in the end.

Heat Was Shot On Location

Nowadays, most of this entire movie would have been shot on soundstages and green screens. Especially when it comes to all of the bullets flying around. However, Heat was made over 20 years ago, long before the days of nearly everything being CGI. Unsurprisingly, Michael Mann filmed the entire movie on location.

Mann filmed using 65 different locations in and around Los Angeles. Not a single scene was shot in a studio, lending more grit to the final product.

Pacino’s Real

Similar to DeNiro, Al Pacino likes to extensively research his roles. although his approach was also far more bombastic than DeNiro’s cool and composed technique. Besides going with the scripted notion that Hanna was a cocaine addict, several lines of dialogue were improvised. This was clearest in the scene with Alan Marciano (Hank Azaria).

While he’s interrogating Charlene Shiherlis’ boyfriend, Pacino’s screaming and his line delivery was totally off the cuff, making Azaria’s reaction 100% genuine. He also inadvertently broke Henry Rollins’ nose while filming their scuffle.

Natalie Portman Loves Guns

Natalie Portman probably doesn’t actually love guns, but she’s been surrounded by them for several years. It’s amazing to look back and see how good of an actress she already was in movies like Leon the Professional.

While her appearance as Lauren is brief in Heat since it was only her second film at the time, she gives a pretty convincing performance as a teen having to deal with her parents’ divorce, her mom’s new boyfriend, and the general pangs of growing up.

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