%% Image and caption selected per Image Pickin' thread: http://tvtropes.org/pmwiki/posts.php?discussion=1359101620053700100
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[[quoteright:350:[[Anime/SaintSeiyaOmega http://static.tvtropes.org/pmwiki/pub/images/Crossroads2_2891.jpg]]]]
[[caption-width-right:350:Two degrees [[Creator/CSLewis eckwards]] of due [[Literature/{{Illuminatus}} fnord,]] [[PeterPan and straight on 'till morning.]]]]

->''"Listen: there's a hell of a good universe next door; let's go."''
-->-- '''Creator/EECummings'''

An ancient trope, still used. Another Dimension refers to universes that are "next" to our own, which require [[InterdimensionalTravelDevice magic or high-end technology]] to travel to and from. In theory, from our world they are in a direction other than the directions we are familiar with.

This term is actually used incorrectly (and let's not talk about "parallel dimensions", which is [[LogicBomb a contradiction in its own right]]). What we usually know as another dimension could be called a "parallel space" in a fourth (or other-th) dimension: that fourth dimension would be the set of all existing alternate spaces.

{{Alternate universe}}s are often just a variety of Another Dimension. Unlike [=AUs=], though, other dimensions don't necessarily have to resemble the "home" universe. There may be a VoidBetweenTheWorlds to go through.

Travel to and from another dimension is usually via some sort of [[PortalDoor door, vortex, portal, gate, window]] -- the exact term depends on the story. Sometimes some kind of [[TransportersAndTeleporters teleportation]] suffices. Characters might need the aid of WeirdnessSearchAndRescue to get home. Entering the dimension can sometimes be used as an ExtradimensionalShortcut.

Despite 'dimension' being a relatively new term for it, the concept is OlderThanDirt. The [[LandOfFaerie "fairy lands"]] of Myth/CelticMythology and European fairy tales, the various universes of Hindu cosmology, {{Hell}}, {{Heaven}} and TheUnderworld, and so on.

Types of Other Dimensions:
* AcidTripDimension
* AlternateUniverse
** AlternateTooniverse
* BeneathTheEarth
* DarkWorld
* ElementalPlane
* InnBetweenTheWorlds
* LandOfFaerie
* LostWorld
* MagicalLand
* MirrorUniverse
* TheMultiverse
* PhantomZone
* PocketDimension
* PrisonDimension
* WhenDimensionsCollide



[[folder:Anime & Manga]]
* This is where the aliens in ''Manga/{{Bokurano}}'' come from. [[spoiler:They're actually humans from alternate timelines, but that [[AwfulTruth revelation]] comes later]].
* Muge Space in ''Anime/{{Dancougar}}''. It is also seen in ''VideoGame/SuperRobotWarsCompact'', ''VideoGame/SuperRobotWarsCompact2'', ''VideoGame/SuperRobotWarsAlpha 3'' and ''VideoGame/SuperRobotWarsGC''.
* The Digital World in ''Franchise/{{Digimon}}'', as described by the human protagonists. Also, the third season of ''Anime/DigimonXrosWars'' has [=DigiQuartz=], a world between the Human and Digimon world.
* ''Popotan'': Where [[spoiler:Shizuku]] dwells.
* ''Manga/SaintSeiya'':
** These are ''weaponized'', used by Gemini Saga [[spoiler: and Kanon]] as a way of removing opponents from the battlefield without much difficulty. Gemini Saga's [[CallingYourAttacks delivery of the attack]] tends to be [[LargeHam really overblown]], to the degree of becoming a MemeticMutation in some fringes of the fandom.
** Phoenix Ikki also uses one at one point [[spoiler: in an attempt to defeat Virgo Shaka by [[HeroicSacrifice sending both he and Shaka there]]. [[DefeatMeansFriendship This earns him Shaka's respect]], and he asks Mu to bring ''both'' Ikki and himself back.]].
** In ''Manga/SaintSeiyaTheLostCanvas'', Saga [[spoiler: and Kanon]]'s predecessors display similar aptitude in the art [[spoiler: and actually uses it at one point to rob a PhysicalGod of the capacity to control time by simply transporting both of them to a dimension where time doesn't exist.]]
** The page image is from successor series ''Anime/SaintSeiyaOmega''. The Gold Saint Gemini Paradox can use the attack "Crossroads Mirage" to put the target outside of time and space so she can show them the effects of the choices they have before them. She uses it to try to force Ryuho to [[SadisticChoice decide between]] betraying his friends or dying through fighting her. The sadistic part comes in that she shows him a utopic future if he betrays them, and thousands dead if he resists. To add extra danger, it ''is'' an actual attack, and it puts the victim body and mind between the two choices and will destroy them via psychic pressure unless they decide.
%%* The Otherworld in ''Manga/YozakuraQuartet''

[[folder:Comic Books]]
* This trope is nearly omnipresent in SuperHero and supernatural comics. A comprehensive list would take up many, many pages.
* Mr. Mxyzptlk, of the ''Comicbook/{{Superman}}'' comics, is from the 5th dimension, a world where everyone's nigh-omnipotent and there's a month called Pants.
* ''Walk-In'' is based around this premise.
* Comicbook/DoctorStrange often travels to other dimensions with [[AcidTripDimension typically psychedelic visual effects]]. His wife Clea was born in one of them.
* ''ComicBook/ShadeTheChangingMan'' comes from a realm with very different dimensional properties.
* A Franchise/WonderWoman villain called The Angler adopts a weapon that allows him to manipulate dimensions, giving him [[TransportersAndTeleporters teleporting]], TimeTravel and travel of TheMultiverse.
* Creator/MarvelComics has an Angler, too; a very minor character with only two appearances, he was radically transformed by being in Another Dimension and though he returns from it, isn't quite suited to "normal" space and tends to be in two places at once. Not to mention crazy, deformed and speaking in weird symbols that look like broken glass.
* The old Earth-One and Earth-Two of Creator/DCComics, now replaced by the Fifty-Two.
* The Franchise/MarvelUniverse is number 616 out of thousands.
* ''ComicBook/{{Zenith}}'' has not only the traditional AlternateUniverse setup, but a dimension outside of spece and time which [[EldritchAbomination the Lloigor]] call home.
* Although the ComicBook/FantasticFour often visit the Negative Zone, it's their UltimateMarvel counterparts who actually use it as part of their SuperHeroOrigin. And they use the nature of other dimensions as a [[spoiler:weapon against Gah Lak Tus]].
* This is also Marvel's favorite HandWave whenever something requires physics-breaking power; [[ComicBook/IncredibleHulk The Hulk]]'s extra mass is taken from one, ComicBook/{{Nightcrawler}} travels through one when teleporting, and ComicBook/{{Cyclops}} gets his eyebeams from one where relativity works differently.
* ''ComicBook/StarTrekTheNextGenerationDoctorWhoAssimilation2''. Hinted at twice in the second issue. The Doctor, who claims to know every star and planet out there, identifies Worf as a Klingon, but then informs Amy and Rory that until seeing him [[RippleEffectProofMemory he'd never heard of a Klingon before.]] Later, when Picard receives the DistressCall from Delta IV, the Doctor [[LampshadeHanging reminds us of his familiarity with the whole of the universe]] and then states he's never heard of Delta IV.
* ''ComicBook/AtomicRobo'': Bad things only happen with other dimensions (the [[OurVampiresAreDifferent dimension of vampires]]), and especially the zorth axis (the EldritchAbomination staking Robo, or the accidental TimeTravel).

[[folder:Fan Works]]
* The [[GodOfEvil Dark Gods']] realm, and the Dark Kingdom in ''FanFic/DungeonKeeperAmi''. Both are alternate dimensions of the ''VideoGame/DungeonKeeper'' and ''Anime/SailorMoon'' dimensions, respectively, themselves in-universe alternate dimensions.
* The Midnight Cage from [[http://alaxr274.deviantart.com/gallery/37280372 Hottie 3: The Best Fan Fic in the World]].
* C'hou in ''Fanfic/WithStringsAttached'' is explicitly set in another dimension; the other planets that the four visit are also in other dimensions. In fact, “universe” and “dimension” are synonymous in this work.
* In keeping with the FantasyKitchenSink MegaCrossover nature of the story, ''Fanfic/ChildOfTheStorm'' has a number of this, including the vast [[Literature/TheDresdenFiles Nevernever]], [[MagicalLand the rest of]] [[TheUnderworld the]] [[{{Film/Thor}} Nine Realms]], Olympus, Avalon, the Negative Zone and the Phantom Zone. Further complicating matters is the implication that some of them blend into one another.
* Termina in ''Fanfic/TheBlueBlurOfTermina'' is this to Sonic's Earth, accessible only via a portal deep within the jungles of Adabat.
* The Realm of the Gods in ''FanFic/TheThreeKingsHunt'' which was inhabited by the Gods and was invaded by the wizards.
* An ''{{Series/Emergency}}'' fic called "Double Fantasy" has character John Gage being switched into the "real" world, where he and his whole world are fictional TV show characters, while actor Randolph Mantooth is trapped in John's world, where John and the rest of the characters are real people.
* ''Fanfic/RoyalHeights'' introduces the idea of the Universe which contains all dimensions and allows them to exist. Students of the academy all come from different dimensions and are able to travel to Utopia via a jet fast enough to rip through their home world into a new one.

[[folder:Films -- Live-Action]]
* A pretty obvious example would be ''Film/TheAdventuresOfBuckarooBanzaiAcrossTheEighthDimension''; crossing dimensions is easy with an Overthruster and a Ford F250. And a [[FiveManBand rock band]] to back you up.
* ''Film/{{Ultraviolet}}'' has this as a HandWave for Violet's {{Hammerspace}} weapons.
* ''Film/FromBeyond'' has another dimension that's [[HyperspaceIsAScaryPlace a scary place.]]
* The original ''WesternAnimation/ThomasTheTankEngine'' show was set on the fictional island of Sodor, which was implied to be located near England. ShiningTimeStation wasn't as explicit but still treated Sodor like a distant land, but for whatever reason ''WesternAnimation/ThomasAndTheMagicRailroad'' turned it into an alternate dimension that could only be accessed with special gold dust or something.
* ''Film/PacificRim'': The Anteverse where the {{Kaiju}} come from, via the [[PortalDoor Breach.]] [[spoiler:At the behest of their Masters.]]

* Most of the adventures in the ''Literature/LoneWolf'' series take place on the world of Magnamund in the plane of Ao. There are other planes of existence such as the Daziarn, a strange dimension divided into mini-dimensions that have almost nothing in common, and the Plane of Darkness, which is basically Hell and the hometurf of Naar the King of the Darkness.

* Edwin Abbot Abbot's ''Literature/{{Flatland}}'' is one of the few examples of the term "another dimension" being used correctly, so perhaps qualifies as a subversion. It is set in a 2D universe where men are geometric shapes, women are straight lines and "up" and "down" are dangerous heresies.
* ''Of Ducks and Universes'' has an alternate universe (at least one) with alternate selves of people born after a certain date (when the universe split into two.)
* Narnia is another dimension in Creator/CSLewis's ''Literature/TheChroniclesOfNarnia'' series of books, with specific rules about [[YearInsideHourOutside time]]. Indeed, the sixth book, ''Literature/TheMagiciansNephew'' provides a very good fantasy description of dimensional travel, likening the space between worlds to the rafters in a block of townhouses. The titular magician also makes it clear that Narnia, Charn, and similar worlds have no geographical relationship to our world at all.
* Creator/PeterFHamilton's ''Literature/TheNightsDawnTrilogy'' incorporates a wide variety of these (scientifically dubbed "continuum's"). The most prominent is the "Beyond", where [[spoiler: most]] souls end up after leaving the body. It's non-spatial, but it has time, so that the souls of the dead are aware of the passage of time but have nothing to do but [[FateWorseThanDeath leech on to each other's memories]] for the feeble semblance of life that they have.
** ''The Dark Continuum'' is as close to an actual Hell as it gets. This is a dimension of near-absolute entropy, where the souls of whoever ends up there are compressed into a zero-Kelvin mass of writhing agony called the Melange. In case you are wondering, yes, they are also fully aware.
** There are also various "pocket universes", not much bigger in volume than a planet, where the Possessed transport the worlds that they steal.
* ''Literature/TheLivesOfChristopherChant'' by Creator/DianaWynneJones uses a similar "place between" which is clearly written in reaction to ''The Magician's Nephew'''s quiet, sleepy Wood Between the Worlds; it's misty, muddy, slippery and somewhat dangerous terrain. There are definitely no guinea pigs.
* ''Literature/AWrinkleInTime'' features a trio of mysterious guardians who are able to transport the protagonists through space via the fifth dimension. According to them, they are able to tesser, or "wrinkle," by [[OurWormholesAreDifferent bending space]] around so that they're in another place in an instant. As one character states: "A straight line is ''not'' necessarily the shortest path between two points."
* Most of Creator/CliveBarker's stories revolve around traveling to and from another dimension, whether through a rug, painting, etc.
* ''Literature/TheChroniclesOfAmber'': After walking a sentient maze and gaining the ability to do so (which nearly all the major characters have done), someone from either Amber or Chaos can walk from world to world, essentially ''willing'' the transfer from one to another. The transfer is gradual, but can do literally ''anything'', including taking the traveler to a world whose mythology predicts the arrival of a deity who looks exactly like him or her. It's mentioned that no one is quite sure whether these dimensions actually exist before an Amber or Chaos resident enters it, but there is currently a sort of two-ended multiverse with Amber at one end and Chaos at the other, with the hundreds or thousands of worlds in between being more similar the closer they are, to both Amber and Chaos, and each other. And the laws of nature don't always work the same from one to another--for example, gunpowder doesn't ignite in Amber. Oh, and all of them except Amber and Chaos are called Shadows, because it's believed that they are only inter-dimensional shadows of the two true worlds.
* In ''The Boy who Reversed Himself'' one could get to the fourth dimension by learning to step 'ana' or 'kata' (the extra directions added to make it 4D) and needed special glasses in order to see more than floating blobs, as our eyes weren't designed for the dimension. "Ana" and "kata" are the ancient Greek words for "up" and "down," respectively.
* Kay Kenyon's ''The Entire and The Rose'' series involves humans discovering a manufactured universe called the Entire. The beings in charge apparently copied sentient species from Earth's universe (the titular Rose) so all the creatures of the Entire supposedly have counterparts elsewhere in our universe that humans just haven't found yet. And there's trouble actually getting to the Entire from the Rose because the beings in charge refuse to share that information. (Those beings themselves and some mysterious attackers called Paion coming from two other universes.)
* Creator/HPLovecraft liked this idea and inserted it into many stories, especially the CthulhuMythos. It was used not only to explain where the various {{Eldritch Abomination}}s hid from the world, but also to explain some of the AlienGeometries of the various structures and beings he created.
* Creator/RobertAHeinlein's ''Literature/TheNumberOfTheBeast'' uses this as a HandWave for traveling TheMultiverse.
* * Creator/BrianLumley's ''Literature/{{Necroscope}}'' and ''Literature/TitusCrow series''.
* The ''Literature/MythAdventures'' series by Robert Asprin has multiple dimensions between which the protagonists often travel. Also, almost all the protagonists originate in different dimensions (Skeeve from Klah, Aahz from Perv etc.)
* Kenneth Bulmer wrote a series about the Contessa Perdita di Monttevarchi, an interdimensional tyrant, and the various people who opposed here
* According to WordOfGod, the races of ''Literature/CodexAlera'' all arrived in the lands of Carna from other dimensions.
* In ''Literature/WickedLovely'': Sorcha's high court, most halflings and sighted ones, [[spoiler: a formerly-mortal dreamwalker named Rae and later Devlin and Ani's 'shadow court']] live in a world known only as [[TheFairFolk Faerie]]. It is also said that the dark court once resided there, but not during the events of the main series.
* Other Dimensions connected to the Literature/{{Discworld}} include [[TheGrimReaper Death's Domain]], [[TheFairFolk Fairyland]], [[CosmicHorrorStory The Dungeon Dimensions]] and [[WelcomeToTheRealWorld Roundworld]].
* It is hard to take other dimensions more seriously than in ''Literature/{{Flatland}}''.
* The Literature/JakubWedrowycz stories feature at least one Another Dimension - it's a MedievalEuropeanFantasy realm with some comedic twists.
* The Territories in ''Literature/TheTalisman.'' Both worlds tend to mirror each other such that doing one thing in one place causes a similar effect in the other. The inhabitants are also mostly the same apart from population differences.
* In Creator/JackVance's ''Literature/{{Lyonesse}}'' trilogy, there is a long section set in Tanjecterly. It's a strange place where trees are different colors, and the heroine is menaced by grotesque, slime-eating creatures called Progressive Eels.
* The concept of another dimension accessible only through special means by special people has been featured in Neil Gaiman's " [[Literature/{{Neverwhere}} Everything]] [[Film/MirrorMask He's]] [[ComicBook/TheSandman Ever]] [[WesternAnimation/{{Coraline}} written]] ".
* [[Literature/{{Reckless}} The Mirrorworld Series]]: The Mirror World is an alternate version of Europe with 1700's politics...cameras, railroads, and [[spoiler: airplanes]]. The primary mode of travel still appears to be horseback, though, and characters don't recognize modern guns or flashlights. Oh, and there's a whole range of supernatural races...
* ''Literature/TheLandOfStories'' take place in a world physically separate from the story’s version of Earth.
* Much of ''Literature/TheRedAndTheRest'' takes place in Papyrus, the world of lost things. Notable landmarks include an enormous mountain of mismatched socks.

[[folder:Live-Action TV]]
* ''Series/BuffyTheVampireSlayer'' / ''Series/{{Angel}}'':
** The demons often hailed from some hell dimension or another; our heroes on ''Angel'' have visited at least three of them. Most of them have different rules on time. For example, on Buffy a demon continuously captured teens to use as slaves, working them until they're in their old age, then finally dumping them crazed and confused back into our world--all of which happened in a matter of a day or two, Earth-time. Also, Connor was sent to the worst dimension imaginable, and came out a couple weeks later as a teenager.
** Glory's world , an Creator/HRGiger type dimension which we see bits of in the Season 5 finale of ''Buffy''.
** There is a running joke about shrimp entirely based on this premise, which has been liberally and enthusiastically embraced by online fandom at large: In "Superstar", when explaining the concept of alternate dimensions, Anya says: "You could have, like, a world with no shrimp. Or with, you know, nothing but shrimp."
*** In "Triangle", after Olaf was banished she said that he could have been sent to "the world without shrimp."
*** In the ''Angel'' episode "Underneath", Illyria talks about moving between dimensions, she said that she went to "a world with nothing but shrimp" but "tired of it quickly."
** The episode "The Wish" introduces an alternate continuity timeline caused by Anyanka, which was supposedly destroyed when her demonic power source was destroyed. But it gets confusing because this alternate timeline is actually ALSO an alternate dimension, since the episode "Doppelg?land" has AU!Willow being pulled from that universe into the primary universe.
* Fluidic space, the area inhabited by Species 8472 in ''Series/StarTrekVoyager''. It's an alternate dimension, only accessed through portals established in the region itself.
* ''Series/{{Sliders}}'' is built on this trope.
* ''Series/DoctorWho'':
** In the 2011 episode "The Curse of the Black Spot", [[spoiler:a spaceship from one dimension was lodged in a pirate ship in ours]].
** Previously, Adric came from Another Dimension called E-Space, which is also where the Doctor left Romana and K9 Mark II.
* ''Series/KamenRiderRyuki'' and its adaptation ''Series/KamenRiderDragonKnight'' both dealt with another dimension on the other side of Earth's mirrors.
* ''Series/KamenRiderDecade'' is similarly about travelling to multiple other dimensions, [[CrisisCrossover all of which are merging into one]]. [[TheHero Tsukasa and co]] visit a new one [[AdventureTowns every fortnight]], with each dimension representing a Kamen Rider series.

[[folder:Tabletop Games]]
* ''TabletopGame/DungeonsAndDragons'' (most notably ''TabletopGame/ForgottenRealms'') features planar travel, based on moral alignments, classical elements and various other things. Of course, the world that most of the action takes place in is the "middle ground". Or so all the Clueless berks think 'till they reach the [[PlaneScape Cage]].
** Mordenkainen's Magnificent Mansion!
* White Wolf's ''TabletopGame/OldWorldOfDarkness'' games featured another set of dimensions called the Umbra, which was based very strongly on [[ClapYourHandsIfYouBelieve human perception]], to the point where a shaman and a scientist in the same part of the deep umbra would see it as a surreal swirling nexus of spirit energy populated with arcane ghosts and a section of interstellar space populated by aliens, respectively.
** The ''TabletopGame/NewWorldOfDarkness'' has its own ''sets'' of dimensions. There's the Shadow Realm, which is like the Umbra, only it's nearly exclusively animistic. Then there's the Underworld, which is home to dead knowledge and concepts and the place where ghosts go when they've [[UnfinishedBusiness finished their business]] but aren't ready to pass on to their final reward. Then there's the Abyss, which is pretty much [[CosmicHorrorStory anti-reality]]. Then there's the five Supernal Realms, dimensions of pure magic. Then there's the Astral Realms, which are where the collective unconscious is made flesh. Then there's Arcadia, which is not the ''Supernal'' Arcadia and is a [[RealityIsOutToLunch constantly shifting]] chaotic wasteland that plays home to TheFairFolk. Then there's the Hedge, the predatory gateway dimension between Earth and Arcadia. And on top of all that, apparently there's ''[[TheLegionsOfHell Hell]]''.
** ''TabletopGame/GeniusTheTransgression'' has smaller Bardos -- pocket worlds made of concepts [[ScienceMarchesOn disproved by science]]. The more prominent ones include an alien-inhabited Mars, the [[Literature/JourneyToTheCenterOfTheEarth Hollow Earth]] (home to [[{{Prehistoria}} dinosaurs]] and [[AnachronismStew cavemen]] and [[StupidJetpackHitler Nazis]]), and the Seattle of Tomorrow, which [[AncientConspiracy Lemuria]] tried to bring into this world [[GoneHorriblyWrong with disastrous consequences]].
* ''[[{{TabletopGame/FateOfTheNornsRagnarok}} Fate of the Norns: Ragnarok]]'' uses the nine worlds of Norse Mythology, located on the branches of the cosmic tree Yggdrasil, each one being its own dimension.
* In Atlas Games' ''TabletopGame/FengShui'', players can [[TimeTravel travel through time]] by means of "The Netherworld", an alternate dimension made up of gray tunnels which lead to [[PortalNetwork portals]] which allow access to and from our world at fixed points in time and space. The Netherworld is home to refugees from alternate timelines that have been erased from reality, including four siblings who ruled the earth in an AlternateHistory.
* ''TabletopGame/{{Warhammer 40000}}'''s [[HyperspaceIsaScaryPlace Warp]] is Another Dimension... [[CosmicHorrorStory 40k style.]] In essence, ''{{Hell}}''. They use it for {{FTL}} travel. It doesn't always ''work''. The ship might disappear then reappear, with everyone inside turned to dust from age. Or it might reappear hundreds to thousands of years later. Or appear at it's destination before it left. "Time" is a funny thing in the Warp. Not funny Ha-Ha.
* The Astral Planes of TabletopGame/{{Shadowrun}}.
* The world of ''TheDarkEye'' consist of seven planes, generally imagined as concentric spheres. The first is unaccessible and "only" a core. The second is a place of raw elemental powers. The third is the one where all the mortal life happens. The fourth is where the souls of the dead rest. The fifth is where the gods dwell, and cosists the paradises particularly worthy mortal souls may be eccepted into. The sixth is the sky with its stars, and some lesser gods can be found here. The seventh sphere is hell, a realm of chaos and infernal cold (ice/cold being the opposite of life in this world's elemental philosophy). In effect, the entire world, from the gods down, is just a relatively insignificant speck in a universe that wants to destroy it.
* ''TabletopGame/InNomine'' is a natural for this trope, possessing not only a {{Heaven}} and {{Hell}}, but also a [[DreamLand Dream World]] known as the Marches, and even a "no-place" called Limbo for the souls of angels/demons who were killed and unable to return to their proper realm.
* Jump Space in ''TabletopGame/{{Traveler}}''. Not much is known about it, as its main purpose is simply to justify FasterThanLightTravel.
* The resistance movement in ''TabletopGame/{{The Splinter}}'' claims that the titular game world is actually one of these.

[[folder:Video Games]]
* See also: FinalBossNewDimension.
* Many ''Franchise/SilentHill'' fans agree that the games take place in a place which is like reality but in some crucial ways different, and the term 'alternate dimension' is a convenient term to describe this, though there are many interpretations of just what that actually means and whether 'dimension' should be replaced with some other, more accurate, term.
* [[TheEmpire The Combine]] from ''VideoGame/HalfLife2'' are a cabal of dimension-spanning PlanetLooters, and the "nearby" -- in 11-dimensional superstring terms, at least -- Xen border-world is the neighboring dimension by which we discover on our own. Xen itself is nebula-like with giant floating asteroids above a bottomless void (and copious amounts of SceneryPorn). At the end of Half-Life 2 we also get a glimpse of the Combine Overworld which looks like a hellish realm dotted with multiple Citadels.
** Xen is also used a a strong plot point since it's a necessary component for Earth-made teleporters. As Mossman explains in [=HL2=], the Resistance "figured out how to use Xen as an unexpressed axis, effectively a "dimensional slingshot" so that we can swing around the border-world and come back into local space without having to pass through". At the end of Half-Life, the dimensional breach left by the resonance cascade was relatively tiny but enough for the Combine who forcibly tore it open and invaded (with the side effects being destructive portal storms and copious amounts of Xen fauna). It was still open in ''Episode Two'' when the Combine tried to call in reinforcements but the rebels screwed up their plans and used Black Mesa's old satellite array to seal it permanently.
** It's worth noting that Xen isn't a "proper" universe; it's [[WordOfGod described]] as a "dimensional travel bottleneck", and is so small, in fact, that its atmosphere is dense enough to be breathable. Add to that the various chunks of planet and the xenofauna from a hundred different worlds, and the impression is that of a "bubble" of spacetime that someone happened to inflate and fill up with just enough material to allow habitability. It's not as unlikely as it sounds, given that [[WordOfGod we know]] [[EldritchAbomination the Nihilanth]] fled there to escape [[TheEmpire The Combine]].
* ''VideoGame/TheDarkness'' features a hell like world that the Darkness resides in.
* ''VideoGame/{{Wolfenstein|2009}}'' (2009) involves a DarkWorld-like dimension called "The Veil". It is our world, just viewed from an inch or so down the fourth spatial axis. But that's not the [[ThoseWackyNazis Axis]] you should be worried about. There's also the [[PocketDimension Black Sun Dimension]], a [[EldritchLocation small, unstable universe]] being held together by the Black Sun at its center.
* ''VideoGame/GalaxyAngel'' begins in EDEN, which consists of a lost civilization and the Transbaal Empire; ''Galaxy Angel II'' brings in two more dimensions, ABSOLUTE and NEUE.
* ''VideoGame/{{Minecraft}}'' has the Overworld, the Nether, and the End.
** The Nether is useful for being a quicker way to travel across the land. One block traveled in the Nether is equal to eight blocks traveled in the Overworld. The player can utilize this by constructing a portal in the Overworld leading to the Nether, travelling a certain distance within the Nether, and then constructing another portal leading back to the Overworld. When the player returns to the Overworld, they will have travelled eight times the distance traversed in the Nether.
* The ''VideoGame/{{Myst}}'' games visit 'Ages' such as Stoneship (inhabited ship, embedded in an island), Mechanical (a clockwork fortress on the surface of the ocean), Riven (water on the five islands shies away from heat sources), Spire (flying, wind-carved ruinous mountains floating above a star), and Ahnonay (cleverly designed to appear to travel through time, to the uninitiated).
* Two of the alien races from ''VideoGame/StarControl II'' come from Another Dimension: the Arilou come from Quasi Space, while the Orz come from a dimension that they refer to only as *below* (thanks to the trouble the TranslatorMicrobes have with their language). The Arilou and the Orz might come from the same dimension, as the Orz say both of the two races are from *outside* and the Arilou are from *above*. It depends on the meaning of *outside*, though.
* April Ryan of ''VideoGame/TheLongestJourney'' jumps between "our" world (Stark) and the mystic Arcadia repeatedly throughout the game. Interestingly, the game's backstory (explained after the first jump) describes a single world, where magic and science existed together. However, it was foreseen that utilizing both of these would result in the destruction of the world, so, with the help of the [[OurDragonsAreDifferent Draic Kin]], the world was split into two main realities and several smaller "pockets" (either intentional or just leftovers). Stark became a world of science and logic, while Arcadia became a world of magic and chaos. Naturally, only humans beings can live in Stark, who have advanced to TwentyMinutesInTheFuture, while Arcadia is populated by all manner of fantasy creatures but is stuck in MedievalStasis. The barrier between the worlds must be constantly maintained, though, as it is clearly unnatural. At some point in the future, the worlds will be re-joined. The major plot point of the game is the fact that, without a Guardian to maintain the Balance, the barrier is starting to break down, with magic seeping into Stark and science seeping into Arcadia. The sequel reveals that, after a new Guardian is installed and repairs the barrier, most of the advanced tech in Stark ceases to function, implying that it's only been functioning thanks to magic (e.g. ArtificialGravity, FTLTravel). At the same time, Arcadia reverts to typical Medieval tech (with all the new "toys" spread by the Vanguard no longer working thanks to the laws of nature being in flux), except for Azadi {{Magitek}}, which uses magic to allow certain primitive pieces of technology to function.
* In ''VideoGame/CityOfHeroes'', quite a few of the high-level missions involve visiting other dimensions or fighting invaders from them.
** As well as the Shadow Shard, a series of 4 zones set in an alternate dimension that may very well be the mind of a god, inhabited by aspects of his personality.
** Also, there is the interdimensional dance club Pocket D, a neutral zone where heroes and villains can get together but are incapable of attacking one another.
* There's a very literal example in ''VideoGame/SuperPaperMario'' where Mario's special move is to "warp" the otherwise flat world, revealing its third dimension. There's also Bestovius, Dimentio and Merloo, who all have dimension-flipping powers! It's quite popular in this game.
* Two alternate dimensions appear in VideoGame/SuperMarioRPG, the Factory where the Smithy Gang came from, and Vanda, where Franchise/FinalFantasy-inspired BonusBoss Culex originates from. Mario and his friends ([[MyFriendsAndZoidberg and Bowser]]) only visit the Factory, the battle against Culex takes place in a [[VoidBetweenTheWorlds rift between Vanda and the Mushroom World]].
* In the original SNES ''VideoGame/StarFox'', there is a secret level titled "Out Of This Dimension" that has to be seen to be believed.
* In ''VideoGame/{{Runescape}}'', there exists a series of gates to the Fairy dimension Zanaris, which itself has a central 'hub' to travel to other, decidedly more hostile dimensions, such as the Abyssal Zone, Dimension X, which is host to horned kangaroos, and even a forest. A forest dimension.
* The Dark Place from ''VideoGame/AlanWake'' is a bizarre realm "beyond the shores of our reality". It is home to more than a few [[EldritchAbomination dark entities]] of [[BlueAndOrangeMorality calamitous intentions]] and it is by nature "fluid", constantly shifting according to the whims and thoughts of its inhabitants; works of art created here or at contact points with our reality (such as Cauldron Lake) can influence reality by coming true. The protagonist, a novelist, writes a book that comes true over the course of the game, and once in the Dark Place itself, finds himself surrounded by words and ideas that he can turn into physical reality, and manifestations of his own fear and hopelessness coming to kill him. It's stated repeatedly that even though signals can travel from it to our reality, once you're in the Dark Place, it is next to impossible to leave, at least withou bringing something ''terrible'' along with you. By the time of ''Alan Wake's American Nightmare'', two years after the first game, Wake has become much more adept at handling the Dark Place and its inhabitants. He is able to write himself as one of the protagonist of one of his works and travel back to our reality at a point of contact (this time near a town in Arizona), but it's hinted that this is not an actual escape and it's not even clear if [[GainaxEnding the events of the game actually took place]].
* ''VideoGame/CliveBarkersUndying'' has both Oneiros and Eternal Autumn, magical realms that are either enslaved or created by two mages in the story, Keisinger and Bethany.
* In the ''Franchise/SonicTheHedgehog'' series, while the two ''VideoGame/{{Sonic Rush|Series}}'' games feature an AlternateUniverse, ''VideoGame/SonicRivals 2'' is about Eggman Nega plotting to free a demon that was trapped in Another Dimension Some theories and other media sources suggest that the Special Zone is Another Dimension. There's also the Twilight Cage from ''VideoGame/SonicChronicles'', which seems to collect powerful civilizations from several dimensions.
* ''VideoGame/MagiciansQuestMysteriousTimes'' has the spirit world, which crosses over with the real world during Mystery Time. During Mystery Time, new bugs and fish appear (including VAMPIRE SQUID), characters from the spirit world appear in the town and require your help, and Mr. Graves (the sleeping skeleton in the room with the organ and locker) wakes up to teach extracurricular classes. Oh yeah, did I mention that the sky turns an otherworldly shade of red?
* Dark Aether of ''VideoGame/MetroidPrime2Echoes'' is a [[DeathWorld Death Dimension]] that literally sucks the life from anything that enters it. It is home to the Ing, spiderlike LegionsOfHell that [[DemonicPossession possess]] creatures of the "Light World" so that they can enter it, as our dimension is just as lethal to them.
* Used in the SNES ''Franchise/ShinMegamiTensei'' games a lot. MajinTenseiII had 2 alternate dimensions. [[spoiler: Amnesia and Paranoia. Amnesia is the realm of the Angels and Paranoia is Lucifer's domain.]]
* ''VideoGame/SuperRobotWarsNEO'' treats Earth Tear from Lord of Lords Ryu Knight this way.
* The ''VideoGame/SuperMarioWorld'' [[GameMod ROM Hack]] series ''VideoGame/TheSecondRealityProject'' features the titular Second Reality. The remake of the first game introduces Thirdspace into the plot.
* ''VideoGame/EarthBoundBeginnings'' has [[spoiler: Maria's]] [[WackyLand Magicant]].
** The fangame ''[[VideoGame/CognitiveDissonance Mother: Cognitive Dissonance]]'' has [[spoiler: Niiue's]] [[WackyLand Magicant]] as well. It also counts as part of [[spoiler: Giegue's]] mind.
** ''VideoGame/EarthBound'' has both [[WackyLand Magicant]] and Moonside.
* ''VideoGame/KirbysReturnToDreamLand'' has the final stage, literally named "Another Dimension", which serves as the game's resident AmazingTechnicolorBattlefield.
* ''VideoGame/DuelSaviorDestiny'' begins when Taiga and his sister are both dragged into the root world by a mysterious red book. It appears to be much smaller and less populous than Earth, but as the core world whatever happens there happens to the outer worlds eventually.
* The later installments of the ''Videogame/DarkParables'' series have begun sending the detective into these. The fourth game had her visit "Fairy Tale Land," and the fifth game trapped her for almost half the game in the "Mirror World."
* The ''Surface'' game series by Creator/ElephantGames are built on this trope. The premise of the games featured the protagonist getting transported to another dimension, usually by supernatural means, and figuring out how to get home. Each game had its own spin on the alternate dimension and stand alone in the series.
* The 10th Dimension in ''Videogame/CrashTwinsanity''. Containing twisted versions of (at least) N.Sanity Island & Slip-Slide Icecapades. May also count as a DarkWorld due to the similarities when compared to the regular dimension.
* ''VideoGame/TheMatrixPathOfNeo'' has one in the Merovingian's chateau, it has it's own {{Bizarrchitecture}}floating maze inside it.

[[folder:Web Comics]]
* In ''Webcomic/{{RetroBlade}}'' there is a 4th Dimension where the Universal Guardian resides, and where Magnus [[spoiler: first obtains the 4D Sword]].
* This is the main plot of the comic ''Webcomic/EmergencyExit''.
* ''Roleplay/EnemyQuest's'' Visitors opened a portal from their dimension to earth and started [[Main/AlienInvasion invading]]. They have their own world back in their dimension: a planet mostly covered in water with a single supercontinent ŕ la Pangaea.
* ''Webcomic/SluggyFreelance'' introduced the Dimensional Flux Agitator, a device that opens portals to other dimensions at random, in its second chapter. The device has been brought back many times since then, to the point where a full fledged [[TheMultiverse multiverse]] has developed.
* ''Webcomic/ElGoonishShive'' has a sub-plot involving alternate dimensions - however it's really just used as another name for {{Alternate Universe}}s.
* ''Webcomic/UnicornJelly'' and its spinoffs are set in other-dimensional realms with their own unique physics.
* In ''Webcomic/PlanesOfEldlor'', demons from another dimension are trying to break into the world.
* This is the premise of ''Webcomic/BetweenTwoWorlds''.
* [[Webcomic/LookingForGroup Richard]] once got banished to the Plane of Suck.
* As of Act 6, ''Webcomic/{{Homestuck}}'' has [[spoiler: three]] currently known parallel universes, [[spoiler: two of which have an AlternateUniverse apiece.]] Each universe also has an [[TrappedInAnotherWorld Incipisphere]] attached to it. The Incipispheres are separate from each other, but all of them are in the [[PlaceBeyondTime Furthest]] [[VoidBetweenTheWorlds Ring]] outside normal reality. And there's also "[[BreakingTheFourthWall the real world]]", which is inhabited by [[AuthorAvatar the author]].
* WebOriginal/JennyEverywhere, the open-source subject of many webcomics, exists in ''all possible dimensions'' and can shift between them.
* ''Webcomic/AmongTheChosen'' features planets with multiple layers of 3D space, so a planet like Earth has alternates in 4D space. [[ViewersAreGeniuses Or something.]]
* ''Webcomic/{{Blindsprings}}'' has the [[TheLostWoods forest otherworld]] in which Tamaura lives at the start of the story.
* In ''Webcomic/AliceAndTheNightmare'', the Wonderland exists alongside Earth and there's some cultural exchange between the two, although it seems that Earth people don't know about Wonderland.

[[folder:Web Original]]
* The Torn World is depicted this way in ''Roleplay/DinoAttackRPG''. It is a mysterious dimension where bricks go when they are [[VideoGame/LEGOIsland torn out of the Constructopedia]]. For some reason every piece breaks up into single-stud bricks (though people are not affected by this phenomenon), which float in the middle of an empty void resembling space, though anything else is still affected by gravity.
* ''Roleplay/TheGamersAlliance'' has several planes of reality, including the Land of the Living, the Land of the Dead, the Void, the High Plane, and the Demon Realm among others.
* Creturia, the parallel world from ''Literature/DimensionHeroes''.
* Similar to ''Sliders'', the whole point of ''AHDotComTheSeries''.
* ''Roleplay/{{Adylheim}}'' has a great deal of these, including a cosmarchy spanning five alternate realities.
* {{Felarya}} is described as a "dimensional plane". Hell and Heaven are both separate dimensions, which mimic the various belief systems of those who arrive there.
* Killer Monster from ''DSBTInsaniT'' resides in one that is essentially Hell.
* ''WebAnimation/{{Dreamscape}}'' has a few, like the Possessor Ghosts realm, which is the ruins of a fortress in a white void, and the Unworld, a bleak world of torment and psychological torture.
* In ''Literature/{{Worm}}'', a GadgeteerGenius named Haywire managed to make a communications link between two {{Alternate Timeline}}s -- they are then dubbed Earth Aleph and Earth Bet.
* ''WebVideo/TheCartoonMan'' saga involves an AlternateTooniverse known as the Second Dimension.
* Deconstructed in ''Machinima/FreemansMind''. Freeman shows a great deal of annoyance over the misuse of the word dimension.
-->'''Gordon:''' I'm pretty sure these aliens are ''three'' dimensional. Probably from somewhere deep in space but space isn't another dimension!

[[folder:Western Animation]]
* ''Franchise/TeenageMutantNinjaTurtles''
** ''WesternAnimation/TeenageMutantNinjaTurtles1987'' had a villain who came from "Dimension X", a world accessible through glowing portals.
** The anniversary movie ''WesternAnimation/TurtlesForever'' posits that every incarnation of the Franchise/TeenageMutantNinjaTurtles comes from a different dimension, and that there is a [[TheEarthPrimeTheory "Turtle Prime" dimension]] from whence all TMNT dimensions originate.
** The Kraang from the ''WesternAnimation/TeenageMutantNinjaTurtles2012'' also come from another dimension and are trying to terraform Earth to look more like their home planet. It's also revealed that they have [[PortalDoor Portal Doors]] to different dimensions, including the one of the [[WesternAnimation/TeenageMutantNinjaTurtles1987 1987 universe]].
* One famous Halloween episode of ''WesternAnimation/TheSimpsons'' has Homer entering the ''third'' dimension. After causing that dimension to collapse, he ends up in the "real" world, "the worst place yet." Like many ''Simpsons'' Halloween sketches, this was a parody of a ''Series/TheTwilightZone1959'' episode.
* Raven of the ''WesternAnimation/TeenTitans'' comes from one of these. She has threatened to deport [[{{Keet}} Beast]] [[SpotTheImposter Boy]] to Another Dimension. She goes to what certainly looks like Another Dimension to deliver a glorified cell phone. Maybe it's so easy for her because [[spoiler:she is a living, humanoid interdimensional portal.]]
* In ''WesternAnimation/JonnyQuestTheRealAdventures'' episode "Other Space," scientists open a portal to another dimension, complete with inhabitants that want to take over ''our'' dimension.
* In the ''WesternAnimation/{{WITCH}}'' TV show and comics that inspired it the [[FiveManBand Five Girl Band]] are appointed as Guardians of the Veil (later [[spoiler:Guardians of the Infinite Dimensions in the show]] to police their Multiverse and prevent various bad guys and the occasional EldritchAbomination from messing things up. In this case "dimensions" seems to mean planes of existence instead of alternate universes as HumanAliens are rarely encountered. Most dimensions fit the fantasy archetype to some degree or another but one world in the comics was an almost literal case of AlienGeometries.
* The Cowboy Universe from ''WesternAnimation/{{Futurama}}'' is identical to our own, except everyone is dressed like a cowboy. While it's described as the only parallel universe in existence, later episodes {{RetCon}}ned it. So it's most likely an Alternate Dimension, given that it's viewable from the edge of the universe.
* ''Franchise/AvatarTheLastAirbender''
** ''WesternAnimation/AvatarTheLastAirbender'' has the Spirit World, a dimension parallel to the one the characters live in. It's home to most of the Avatar world's spirits, and the former incarnations of the Avatar itself, and seems to operate on a completely different kind of physics. The titular Avatar is the bridge between the show's two dimensions, as a fusion of a human and the BigGood spirit of light and peace, Raava. We only ever see Aang visit the Spirit World, but Sokka [[TakeOurWordForIt apparently]] got stuck there for 24 hours, and it's heavily implied that Iroh has been there as well, presumably indicating anyone can get there if they try hard enough. There are also several spirits (Wan Shi Tong, Tui, La, and Hei Bai) who have visited the physical world.
** ''WesternAnimation/TheLegendOfKorra'' expands the Spirit World first seen in ''Avatar''. After his death, Iroh AscendedToAHigherPlaneOfExistence and ended up there. Spirit portals are opened and created, leading to thousands of spirits living in the material world, and many regular people like [[EnlightenedAntagonist Zaheer]], Aiwei, and Jinora are capable of meditating there.
* ''WesternAnimation/AdventureTime'' has [[AcidTripDimension Lumpy Space]], the [[TheUnderworld Land of the Dead]] (plus ''at least forty-nine other'' dead worlds apparently), the Crystal Dimension, and [[FireAndBrimstoneHell the Nightosphere]].
* In ''WesternAnimation/BarbieAndTheSecretDoor'', the Secret Door leads to the magicla kingdom of Zinnia.
* Star Butterfly from ''WesternAnimation/StarVsTheForcesOfEvil'' is from one of these, called Mewni and based heavily off of standard fantasy settings. It's even in the show's ThemeSong.
* ''WesternAnimation/DrDimensionpants'' features multiple other dimensions that excist besides the one the hero hails from.
* ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' has the starry realm that Twilight went to when she ascended to alicorn status. Also, in 'Make New Friends but Keep Discord' it is revealed Discord can open portals into other dimensions, one of which he lives in, and one of which contains live-action sock puppets.
* ''WesternAnimation/PennZeroPartTimeHero'' revolves around three {{Punch Clock Hero}}es who have to travel to other dimensions and take over the bodies of various denizens in order to save the world they're in.

[[folder:Real Life]]
* In string theory, which is the highly speculative Hot New Thing in theoretical physics for the last few years, our visible cosmos is located in a ten- or eleven-dimensional hyperspace, which may contain an arbitrary number of other continua, with varying kinds of matter, forces, and numbers of dimensions.