1 | Inception

The last shot of Inception focuses on a shot of Dom Cobb's (Leonardo DiCaprio) "totem" top still spinning, indicating he may be stuck inside a dream world. Star Michael Caine says that Cobb was in the real world, while director Christopher Nolan takes the more philosophical stance of, "The way the end of that film worked . . . [Cobb] didn't really care any more, and that makes a statement: perhaps, all levels of reality are valid." For more great Hollywood coverage, check out our list of the best fight scenes in movie history. 

2 | Memento

Yes, Nolan's first brain-teaser of a movie, Memento, is told backwards-and-forwards through the perspective of a man who can't form new memories. Said protagonist Leonard Shelby (Guy Pearce) is supposedly hunting down the killer of his dead wife, only to be told at the end by a shady cop that he murdered his wife by overdosing her on insulin. But Memento is a movie built around the idea of ambiguity—of memory, and of people—and the whole truth is never really made clear, leaving viewers to decide for themselves what they want to believe. And here are some sorely underrated Ryan Reynolds movies that even you movie buffs probably haven't seen. 

3 | Shutter Island

Another Leonardo DiCaprio flick, his protagonist Teddy Daniels believes himself to be a U.S. Marshall investigating an insane asylum, that, he discovers, he is actually a patient of. The movie ends with Daniels seemingly slipping back into insanity, and thus has to undergo a lobotomy, but a cryptic comment Daniels makes to his "partner" indicates that a still-sane Daniels is simply choosing to " . . . die as a good man." Roles in complex, mind-bending roles like these are just one reason Leonardo DiCaprio remains one of the coolest men in Hollywood.

4 | The Shining

Stanley Kubrick's acclaimed adaptation of a Stephen King's novel focuses on writer Jack Torrance (Jack Nicholson in one of his most acclaimed roles) who takes a job as a hotel caretaker for one winter, in the course of which he goes insane. Unless, of course, he was always the caretaker, as the final shot of Nicholson hosting a July 4th party in 1921 at the hotel seems to imply. This movie has inspired so many fan theories and debates that they have become the subject of a movie themselves, the documentary Room 237. When it comes time to your own July 4th celebrations, check out the 15 goddesses that rocked an American flag this year.

5 | Lost in Translation

Director Sofia Coppola's mesmerizing story of a middle-aged movie star (Bill Murray) striking up an unlikely friendship with a newlywed (Scarlett Johansson) ends on a shot of Murray whispering something into Johansson's ear. Said whisper has become one of cinema's greatest mysteries, even Coppola says she doesn't know, as that bit was improvised by Bill Murray. Tech savvy film buffs have tried to suss out the dialogue over the years, although nothing definitive has emerged. So hats off to Murray, avid golfer and master improviser. 

6 | The Wrestler

Darren Aronofsky's heart-wrenching drama about a washed up wrestler desperate to reclaim his glory years ends with Randy "The Ram" Robinson (Mickey Rourke) suffering from chest pains in the ring, indicating that the heart condition a doctor warned could kill him if he kept wrestling is about to flare up. The credits roll before viewers can see what finally happens to Randy, but the real tragedy is that Randy probably didn't have anything left to live for at that point.

7 | Taxi Driver

None other than esteemed film critic Roger Ebert raised the possibility that the ending of Martin Scorsese's dark masterpiece, in which protagonist Travis Bickle (Robert DeNiro) becomes celebrated for his violent rescue of a teenage prostitute played by Jodie Foster, is simply the fantastical delusion of a dying Bickle. It's a wonder this film didn't make our list of the 20 best car chases of all time, ever.

8 | 2001: A Space Odyssey

Another Kubrick masterpiece, the ending of this sci-fi epic sees astronaut Dr. David Bowman (Keir Dullea) pulled through mysterious stargate and "beyond the infinite" into a mysterious bedroom and eventually transforming into a cosmic star-child. Ok, so words don't really do this sequence justice, as it is a feast of visuals and effects that few, if any, modern directors could pull off. The movie never explains what, exactly, is going on, but the finale is so awe-inspiring to watch that it doesn't even matter.

9 | The Graduate

This 1967-flick stars Dustin Hoffman as Benjamin Braddock, a wayward college graduate unsure of what he wants to do with his life. Eventually, he convinces his love interest Elaine Robinson (Katherine Ross) to run away with him, but as the pair are riding away on a bus they are hit by the greatest mystery of all—the mystery of just what lies ahead in their future. The Graduate has a lot to recommend it, including two of the best Simon and Garfunkel songs in its soundtrack, but the final shot of Hoffman and Ross staring blankly ahead in uncertainty propelled the film into pop culture touchstone status. The film inspired Mrs. Robinsons everywhere, including these 10 celebrity couples.

10 | Birdman

At the end of this recent Best Picture winner, the insane, washed-up actor Riggan Thompson (Michael Keaton) jumps out of a windowsill, believing himself to actually possess the titular Birdman's super powers. His daughter (Emma Stone) sees and rushes out to the open window and looks up in... joy? Did Riggan actually have superpowers? Was his daughter insane? Is this another dying-man's-fantasy ending? I suppose we'll have to wait for Birdman Returns for the answer. For more are-they-are-they-not hero stories, check out the 11 times celebrities were real life heroes.

11 | In Bruges

Colin Farrell gave what might be his greatest performance as Ray, a depressed, guilt-wrecked Irish mobster who, at the end of the film, is being rushed to the hospital and on the edge of death due to gunshot wounds. Ray's final fate is unknown, but the ambiguity and in-between-life-and-death nature of the character's ending may have been inspired the concept of Purgatory, given how much writer-director Martin McDonagh appears to have been inspired by Catholic dogma for this black comedy.

12 | American Psycho

This violent satire of yuppie culture features a young Christian Bale as Patrick Bateman, a Wall Street Banker and serial killer. Yet just as Bateman's acts of gruesome murder seem to reach their boiling point, it's revealed that at least some of Bateman's murders never happened, raising questions as to how much of the film was actually real and how much of it was the delusional fantasies of a sociopathic member of high society. Side note: a lot of actors turned down this role; read all about the story here.

13 | The Sopranos

Astute readers will note that The Sopranos was in fact a television show, and not a movie. This is true. But no discussion of ambiguous endings would really feel complete without this epic mob saga's infamous cut to black moment, leaving the final fate of Tony Soprano up in the air. Some fans believe that the finale was simply an attempt to depict the constant ceaseless anxiety that a man of Tony's chosen profession must experience, while others argue, in extraordinary depth, that Tony was killed.

14 | Mulholland Drive

OK, so this entire movie is a mystery, and your guess is as good as ours.

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