The following is a list of [[secrets]], Easter eggs, and hidden trivia references in [[Grand Theft Auto IV]].
* Inside the [[Statue of Happiness]] is a giant beating heart. This is supposedly the "Heart of [[Liberty City in GTA IV Era|Liberty City]]."
* Whilst on a mission with [[Patrick_McReary|Packie]], if you position the camera properly you can look inside his head - inside there is a box with a picture of a brain on it.
* In the North of Alderney, where you make the jump in the mission [[Out of Commission]], there is a person doing tai-chi on top of a high rock which is impossible to get to without a helicopter.
* If you look at the lake in [[Middle Park]] by map or helicopter, you'll notice it is in the shape of an alien.
* While driving the [[Mr. Tasty]], you can trigger songs to play by clicking the horn. One of these songs is the song from the opening credits of GTA4. While this song is playing, call ZiT and they will text you back with "ZiT! Spotted GTA IV Theme". This is a cheat that gives the player health, armor and ammo, but also disables some achievements.
* If you take a helicopter ride from [[Brucie Kibbutz]], or you go for a helitour, there's an unsettling warning message about the helicopter inside the cockpit that you can see if you look in first person mode that says ''"This helicopter might crash but we really don't care if it does, refer to flight manual for help."''
*At the [[Firefly Projects]], there is a park with a swingset. If you drive backwards (or forwards with some vehicles; Voodoo) onto it, the swingset will catapult the vehicle you're in high in the air. This is likely a bug in the game's physics simulation.
*If you are driving a car or bike at an incredible speed, go to your cellphone and go to camera and when you select camera, no matter at what speed you are going your vehicle will come to an instant stop (does not work on PC version).
*When you have a house in Bohan, when you exit, you can see a radom NPC talking about the end of the world and the Apocalypse. Enter the building next to him and after you get up a few stairs, in a passage you can see blood and a pistol on a floor.
*On one of Brucie's mission "Easy as Can Be", If you look on the lower part of his stomach, you will see a tattoo that says "Mommy" on his stomach. You will be able to see that when he has his shirt off.
* Behind an old, rundown mansion in [[Westdyke]], [[Alderney]] at the end of the dirt roads, there is the hidden, extremely rare [[Sultan RS]] parked in some bushes. This is practically the only way to find the car ingame. The only other way to obtain it is if the game has it stored in the temporary memory, and automatically spawns it parked and driving around the streets.
* On the west side of Happiness Island there is a random spawn that can be a car. This is unusual as there is no way a vehicle can be brought on to the island unless unloaded by a ship.
==References to previous games==
* On the Mission "First Date", If you selected "Try your Luck", Niko will ask if he can come in for coffee, then Michelle will say "Yeah, for 20 million dollars". This is a reference to the "[[Hot Coffee]]" controversy which describes the lawsuit.
* Descending down the stairs of your first apartment in [[Hove Beach]], you may spot some graffiti referring to past GTA protagonists [[Claude]], [[Tommy Vercetti|Tommy]], [[Carl Johnson|Carl (CJ)]], [[Toni Cipriani|Toni]], and [[Vic Vance|Vic]] suggesting they have passed away. This can also be seen in the building adjacent to [[Playboy X's Penthouse]]. This could be referring to the fact that since the characters of previous games are part of a separate canon, they will not appear or be referred to in later games as they were in the GTA III era. The characters may not be dead, but they exist outside of GTA IV's storyline.
* There is a [[Sprunk]] manufacturing plant in [[Alderney]]. Sprunk was featured in [[GTA Vice City]], [[GTA San Andreas]], and [[Manhunt]]. It has returned to GTA IV with a brand new look. Also notice that "Sprunk" is a mix of the words "Sprite" and "Spunk". The sign outside the factory is very similar to a sign for Pepsi-Cola that appears in the film "The Great Gatsby."
* One of the [[TV Shows in GTA IV|TV shows]] is a program called ''The Venturas Poker Challenge''. It features a casino in [[Las Venturas]] from [[GTA San Andreas]].
* In [[Star Junction]] there is sign for [[Love Fist]]. Love Fist was featured in GTA Vice City, and was also on a sign in GTA San Andreas and GTA Liberty City Stories.
* In the apartment in [[Bohan]], next to the coffee table and in front of the bed, are a few CDs laying on the floor. Zoom in with a sniper to see that one of the CDs is by [[OG Loc]] from GTA San Andreas. There is also one by [[Madd Dogg]].
* There is a laundromat in Alderney called [[Mr. Wong's Laundromat]]; this is presumably either the same one from [[GTA III]] or a nod to that particular location.
* When you kill [[Playboy X]], go to his apartment and open the wardrobe to get a change of clothes that that look like the clothing of [[Claude]], the protagonist of GTA III.
* On the front of the [[Liberty Tree]] is [[Donald Love]], who disappeared in GTA III.
* The [[Securicar]]s are apparently still owned by the [[Gruppe Sechs]] security firm (as seen in GTA III and Vice City), although in GTA IV the name is rendered as "Gruppe 6".
* In the bars are postcards featuring [[Vice City]]. Vice City is also advertised in airfare billboards near the airport.
* The "Pager" ringtone on Niko's [[cell phone]] is the pager sound from GTA III.
* Niko can receive an email from Chiliad8888, which calls the recipient "Pilgrim", makes many spiritually- and philosophically-charged (and anti-government) comments, ends with "Feel the Truth, Live the Freedom", and links to [[whattheydonotwantyoutoknow.com]]. On this website there is a discussion topic titled, "Jump to a new level of Spirituality" posted by "Trooth". This discussion thread includes more philosophical thoughts, mentions [[peyote]], and provides a map of the [[Unique Stunt Jumps]] in [[Liberty City in GTA IV Era|Liberty City]]. "Chiliad" was also the name of a location in San Andreas (the highest mountain, in the southwestern wilderness). These clues suggest that the author of the email and discussion topic is [[The Truth]], a character from [[GTA San Andreas]].
*On [[Happiness Island]], in front of the entrance to the statue, it is possible to find a street-artist's easel/display stand with several pictures. These pictures are all concept works of many previous GTA characters. The easel can also be seen in south-central Algonquin, very close to where [[Hossan]]'s [[Random_Characters|random encounter]] takes place.
* In Alderney, off Bowline and near the Mr. Fux's Rice Box eatery, is a restaurant named the "Greasy Joe's Cafe", a most likely reference to the [[Greasy Joe's]] back in GTA3. There is a little sideline mention in the restaurant section on Public Liberty Online dot com.
* Awhile after the mission [[Diamonds Are a Girl's Best Friend]], the news reports that a homeless man found the diamonds used in the exchange and planned to use the money to open a gun store in [[Vice City]].
[[Image:th_GTAIVGreasyJoesCafe.jpg | right|]]
==References to other games==
* In the amusement park in [[Broker]] there are blue/purple Hippo Statues, just like the ones from [[Manhunt]].
* On the TV channel WEAZEL, there is an animated tv show called Republican Space Rangers, which spoofs the Halo series, as it features southern homophobic rascist soldiers wearing green Spartan-type armor invading a foreign friendly planet. They fly in a spaceship shaped like a penis and fly through a ring like the HALO Rings, an obvious reference to sex.
:''For GTA IV's renditions of New York City landmarks, see [[Liberty City in GTA IV/New York Landmarks]].''
* The game references to the economic recession faced by the United States on a few occasions.
* [[Rockstar Games]] has a habit of putting its logo in its games; the bowling pins at the [[Memory Lanes|bowling alley]] have the Rockstar logo on them.
* In [[Cluckin' Bell]] restaurants, near the back of the store, there's an action figure of a man in a martial arts position wearing a chicken hat; printed on the glass is "Cluck Norris," a reference to film/television star and martial artist [http://en.wikipedia.org/wiki/Chuck_Norris Chuck Norris].
*When the [[police]] get shot and don't die they sometimes scream "I'm going to be OK. I'm going to be OK!" A reference to the movie [http://en.wikipedia.org/wiki/Reservoir_Dogs Reservoir Dogs].
* The mission [[Weekend at Florian's]] is a reference to the comedy movie ''[[Wikipedia:Weekend at Bernie's|Weekend at Bernie's]]'' (Florian insists that his new name is Bernie).
* The mission called [[I Need Your Clothes, Your Boots and Your Motorcycle]] is a reference to [http://en.wikipedia.org/wiki/Terminator_2:_Judgment_Day Terminator 2: Judgment Day], in which [http://en.wikipedia.org/wiki/Arnold_Schwarzenegger Arnold Schwarzenegger] says this famous line.
*The mission [[The Puerto Rican Connection]] is named after the movie ''The French Connection'' which features an El-Train chase, similiar to the mission.
* Many street names in [[Bohan]] are named after prisons -- Leavenworth Ave, Alcatraz Ave, Sing Sing Ave, Guantanamo Ave, Attica Ave, San Quentin Ave, Folsom Way (best known from "Folsom Prison Blues" by Johnny Cash), Rykers Ave (named after the Rikers Island prison on the East River of New York City), Joliet Street.
* Streets running east-to-west (horizontally) in [[Algonquin]] are named alphabetically after different types of minerals. "A" is at the southern end of Algonquin; "X" at the northern end. The names include Amethyst, Barium, Calcium, Diamond, Emerald, Feldspar, Garnet, Hematite, Iron, Jade, Kunzite, Lorimar, Manganese, Nickel, Obsidian, Pyrite, Quartz, Ruby, Silicon, Topaz, Uranium, Vauxite, Wardite, Xenotime
* In the South of [[Alderney]], the street names reflect (mostly antiquated) military terms -- Musketeer, Grenadier, Chariot, Phalanx etc.
* In Broker, roads running North-South are named after Native American tribes -- Iroquois, Oneida, Mohawk, Onondaga etc.
* In south [[Dukes]] and north Broker there are the street names "Cassidy" and "Sundance", a reference to the film Butch Cassidy and the Sundance Kid.
* Broker contains the streets "Ringo St" and "Starr St", a reference to the Beatles member Ringo Starr.
* Rockstar uses cartoon characters names as street names such as, "Bart (Simpson), (Hubert) Farnsworth" and the direct link to South Park, "South Parkway".
* Some streets are named after tools -- Jackhammer, Plumbbob, Tinderbox.
* Some streets are named after animals -- Caterpillar, Worm, Butterfly.
* Some streets are named after foods -- Onion, Asparagus, Chive.
* Some streets are named after colonial Settlements -- Yorktown, Delaware.
* Some streets are named after famous surnames, -- Harrison, Hancock, Livingstone.
* Some streets are named after nuclear tests -- Plumbbob, Emery, and Niblick.
* On the [[Algonquin Bridge]] from [[Algonquin]] to [[Broker]], on the right is a building with the name "CLOCKTOWER"; this is the reminiscent of the "WATCHTOWER" building of the Society of the Jehovah's Witnesses in Brooklyn.
* At the beginning of [[Clean Getaway]], [[Vlad]] is nearly hit by a taxi and shouts "Hey! I'm walking here!" in reference to the movie ''[[Wikipedia:Midnight Cowboy|Midnight Cowboy]]''.
* On the stairway leading to the sea at Meadow Hills there is a '[http://en.wikipedia.org/wiki/Banksy Banksy]-esque' style graffiti piece.
* On the sides of some [[Sentinel]]s are a little pink "''STD''," referring to Subaru's pink "STi".
* There is a [[Liberty Tree]] article that talks about urban myths in Liberty City. This could be referring to the myths that were created around San Andreas.
* An [[Internet in GTA IV|online]] article on [[Liberty Tree]]'s [[Libertytreeonline.com|website]], an Air Sol flight has 212 passengers onboard, 212 a reference to the area code in New York City.
* In [[Willis]], there is a shop called Al's Furniture. This is an obvious reference to Italian-American gangster Al Capone, who was officially the owner of a furniture shop.
* The fact that a secretive government body operates out of a paper factory may be a reference to the TV show [http://en.wikipedia.org/wiki/Heroes Heroes]. A secretive organisation in that show also uses a paper factory as a cover and much of the action takes place in New York.
* The outside sign for the [[Memory Lanes]] bowling alley depicts a bowling pin with two bowling balls on either side of it. Inside, however, the sign is only a neon outline, and resembles a crude drawing of male sex organs.
* In many spots around Liberty City, there is rubble on the ground; in some of this rubble, you can see a purple dildo sticking out.
* There are signs scattered throughout Liberty City that say 'Hot Coffee Shop,' clearly a reference to the [[Hot Coffee]] sexual content and controversy from [[GTA San Andreas]]
* Looking at the golf courses carefully from a height reveals that they are penis-shaped.
* A brand of beer in the game is called 'Dusche Gold.' "Dusche" is German for "shower", so it translates into "Shower of Gold."
* Another beer brand (presumably spoofing Budweiser) is named "[[Piswasser]]", "wasser" being German for "water".
* The logo for [[Piswasser]] shows a woman with the bottle in her mouth as if in an act of felatio
* The logo for AutoErotica is a car resembling a penis
* In the Cluckin' Bell at the Star Junction the Girl's bathroom has the word Chicks and the Boy's has the word Cocks.
* In east island city there is a building called the national union of contemporary arts. It is located directly across the street from a PillPharm and Badman encounter. If you walk into the courtyard you will see a statue of what looks like a stick figure man with an erection.