Season 5 is in full swing, and if you're anything like me, you are already obsessing over Pretty Little Liars' latest questions. This isn't your ordinary teen drama — it's a full blown mystery series with twists, red herrings, and insane reveals set against a Young Adult television backdrop. Pretty Little Liars may be a unique hour of television, but the show itself hardly exists in a bubble. One of the most interesting aspects of Pretty Little Liars is the show's ability to play homage to a variety of literary and film works that came before it — and I'm not just talking about Gossip Girl and its obsession with Audrey Hepburn. (Though, let's be honest, A totally borrowed some snarky dialogue from the Upper East Side gossip blogger.)

Pretty Little Liars is constantly referencing movies within the series, some of which the show plays an obvious homage to. (The Season 4 episode "Shadow Play" was shown almost entirely in black-and-white, and nodded to the noir films of the '40s.) Other Pretty Little Liars movie references are far more subtle, and act as a wink at cinephiles. Here are just a few of the film references that Pretty Little Liars have included so far — there's sure to be more to come.

American Film Noir

Pretty Little Liars borrows heavily from the themes of '40s and '50s American film noir, which is generally defined as a crime drama marked by a bleak mood and general pessimism. I think Spencer Hastings gets it:

Pretty Little Liars in itself is a contemporary take on noir — the girls exist in a world where no one is to be trusted, including themselves. (Remember Spencer's freak out when she thought that she had killed Alison?) The show played the most obvious homage to American film noir in Season 4's "Shadow Play," which had the characters play out an episode as though it were set in the '40s.

Executive producer Joseph Dougherty stated that he specifically played homage to the 1944 film Laura in PLL 's "Shadow Play," and considering the plot of the film, it makes enormous sense. Laura is about a detective investigating the murder of beautiful woman, only to learn that she had never been killed at all. (Sound familiar?) Alison's portrait in "Shadow Play" is a direct connection to Laura.

More recently, the show referenced another film noir — this time, in living color. In Season 5's "Whirly Girl," Mona shows Aria her new "anti-kidnapping" whistles, and tells Aria, "It's a whistle. You put it between your lips and blow." It's Lauren Bacall's famous line, cut directly from the 1944 romance To Have and Have Not. In the Season 4 Halloween episode "This Is A Dark Ride," Spencer, channeling film noir with her costume, says the first part of that line: "You know how to whistle, don't you?"

Classic Horror Films

There are times when Pretty Little Liars is downright frightening. (There are way too many scary masks on this show.) It's not surprising that PLL borrowed heavily from the horror genre — what's a murder mystery without a good scare, right? The 1973 movie Don't Look Now has had a huge impact on the PLL plot — not to mention Ali's wardrobe.

In Pretty Little Liars, the girls spend almost an entire season chasing down the elusive "red coat," whom they believe is Alison, despite being told that Alison was dead. In Don't Look Now, a grieving father chases down a blond girl in a red coat, and believes her to be his deceased daughter. I won't give the ending away, but let's just say that this movie's outcome is certainly more frightening than that of any PLL finale.

Pretty Little Liars is peppered with horror references, from the many "scary carnival" scenes (which could be interpreted as an allusion to 1983 evil carnival film Something Wicked This Way Comes) to the "omnipotent antagonist" of A, who is easily be a throwback to '90s horror flicks like I Know What You Did Last Summer. And how about those chilling masks?

According to showrunner I. Marlene King, the "zombie babydoll stalker" costume is a creation of Mandi Lane, the costume designer. (The mask itself is available for purchase, if you want to horrify all of your friends.) Though the mask may be an original PLL creation, masked stalkers are a horror film staple. Friday the 13th, Halloween, and parody film Scream all have their own masked figures, PLL's packs the most punch, if you ask me.

Hitchcock Films

Alfred Hitchcock's films could fall under the horror category, but PLL's heavy use of Hitchcock film throwbacks far surpasses any of the references from the other films on this list. PLL is peppered with references to what is arguably Hitchcock's most famous film, 1960's Psycho. Perhaps the most clear example of the Psycho allusion is in Season 2, when the girls first venture to the "Lost Woods" resort. The resort is set up almost identically to the "Bates Motel" in Psycho — and the man they meet, Harold Crane, is a dead ringer for Norman Bates.

Later in the season, when the girls finally unmask A (the Season 2 finale "unmAsked,") and learn that it was Mona who was their stalker all along, Mona goes full Norman. Remember Mona's mental breakdown in Radley? It's an allusion to Norman Bates' own lockup at the end of Psycho.

Smaller Hitchcock references in PLL include a scene where Hanna is staring out her window while in her wheelchair after the hit and run. According to TV director Norman Buckley, that scene was straight out of Hitchock's Rear Window . The Season 1 finale "For Whom the Bell Tolls" also features a Hitchcock reference: Spencer running away from Ian is a mirror of Jimmy Stewart's Detective Ferguson chasing after Kim Novak's Madeleine Elster before she can commit suicide in Hitchcock's Vertigo.

Pretty Little Liars' short-lived spinoff also referenced a Hitchcock classic: The Birds. Thankfully, the show didn't last long enough for the series to have anyone's eyes get pecked out by ravens, for which I am eternally grateful.

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