[[quoteright:250:[[VideoGame/{{Grandia}} http://static.tvtropes.org/pmwiki/pub/images/GrandiaMap_9067.jpg]]]]
[[caption-width-right:250:When neighbors from another ''continent'' get too noisy.]]

All around where you grew up is a barrier. No one knows what lies on the other side. Or if they do, they're not telling. It could be HereThereBeDragons, or your ancient enemies, or it could be that you and everyone you know is SealedGoodInACan (or [[SealedEvilInACan evil]], who knows?). Passage through will be difficult if not impossible, for what good is a barrier if anyone can walk on through?

The wall can surround a single village, a town, a continent, a world, or even [[CorralledCosmos an entire galaxy]]. Or it could seemingly surround nothing, and simply mark a barrier between one world and the next. Surprisingly common in Soviet era SF. Think about it.

Note that, despite the name, the barrier does not have to be a literal wall.

If the barrier surrounds a community, it is an isolated SmallSecludedWorld or CityInABottle or possibly a DomedHometown. Contrast with TheGreatWall.
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!!Examples:

[[foldercontrol]]

[[folder:Anime & Manga]]
* The wall around the town in ''HaibaneRenmei''. (We never do find out what lies beyond, though considering that the walls are [[spoiler:death]]...)
* In the first and second seasons of ''{{Slayers}}'', the world Lina could explore (and put craters into) was restricted by a magical barrier that went down after the BigBad powering it was killed.
* The wall in ''PrincessTutu'' is both literal and metaphorical, keeping reality from intervening in the [[TheoryOfNarrativeCausality narrative-controlled]] Gold Crown Town. Most people don't even realize it exists, since the story prevents them from wanting to leave. (This doesn't stop people from suddenly appearing inside the town gates, but it's ambiguous whether they're capable of leaving.)
* ''Anime/TengenToppaGurrenLagann'' has the human villages deep underground. The planet's surface is overrun with monsters, and humanity has hidden away for so long that most of the people in Kamina's village question whether the surface actually exists.
* In the oneshot manga ''Island'', by Komi Naoshi, the town the main characters live in is surrounded by a huge wall, much like a well. When the islanders turn 14, they are shown the truth- outside their island is nothing but a vast sea. [[spoiler: The islanders believe that all the land in the world sunk and thus all other countries were drowned, making it useless to go outside the island. It turns out that only the island sank, probably because of land subsidence and earthquakes.]]
* Tokyo Jupiter in ''RahXephon'', encasing Tokyo ([[ExactlyWhatItSaysOnTheTin and looking like Jupiter]]).
* A variety occurs in ''Anime/AngelBeats''. There's no literal wall, but the world around the high school complex just disappears into a thick fog once you travel beyond the hills.
* The "spiritual barrier" around the village in ''Literature/FromTheNewWorld''. The humans inside the barrier are told never to cross it, because the outside world is full of horrific monsters. [[spoiler:They are taught this so that their subconscious telekinesis will only create said monsters outside the barrier. The barrier keeps bad things out ''and'' imprisons the characters, by necessity.]]
* In ''Manga/AttackOnTitan'', the remnants of humanity live inside an area protected by three absolutely massive ring walls. All the lands outside are claimed by man-eating giants that have hunted humanity to near extinction. The plot of the series is kicked off when the walls begin to fail...
[[/folder]]

[[folder:Comic Books]]
* The ComicBook/IncredibleHulk occasionally visited the Keystone Quadrant in his old comic-book series... basically a solar-system (possibly more than one) which was somehow 'walled off' from the rest of the universe, it could only be entered and exited through various types of teleportation. It was basically a SugarBowl without the sugar - populated by funny talking animals and hilariously incompetent Keystone Kops... and caught up in a long war between a MadScientist tortoise and his cybernetically-enhanced Black Bunny Brigade (not to mention a small army of robotic [[MonsterClown Monster Clowns]]), and the heroic Animal Resistance, led by a fast-talking Raccoon space-captain.
* The Source Wall is a wall around the entire {{DCU}}, which...well, who fucking knows. It makes no sense. Either 2D Space is in full effect or it lines the entire interior of the universe, in which case the universe it both finite and shaped in a way where that makes sense. Also, there are powerful cosmic beings embedded in the wall, and The Source (which may or may not be God) is on the other side.
[[/folder]]

[[folder:Film]]
* The forest containing ''TheVillage'' is closed off from the outside world by a wall. Turns out there's a reason for that.
* The desert that surrounds the Maitlands's house in ''Film/{{Beetlejuice}}''.
* The walls of Truman's enclosed world in ''Film/TheTrumanShow''.
* The broken bridge in ''Dellamorte Dellamore'', aka ''Film/CemeteryMan''.
* In ''Film/DarkCity'', John Murdoch tries to reach Shell Beach; instead he finds a wall at the edge of the city.
* In the film version of ''Film/AeonFlux'' the survivors of the "industrial virus" (biological apocalypse) have lived in the walled city of Brenga for generations. The outer perimeter of the wall is periodically sprayed with some sort of poison to keep the outside world at bay.
* A (probably apocryphal) story about HarlanEllison's pitch for the first ''Franchise/StarTrek'' film claims that Ellison met with Paramount executives and provided an outline for an epic story which ended with the crew of the ''Enterprise'' traveling to the edge of the universe, encountering a massive wall there, blasting a hole through it with their phasers, and ''seeing the eye of God staring back at them''. Studio heads, however, were unimpressed, claiming that the premise wasn't "big enough", at which point Ellison stormed out of the meeting.
* In ''TheLastStarfighter'', the entire civilized-good-guys portion of the galaxy is surrounded by an enormous force field called the Frontier. The evil Ko-Dan Armada lies outside the Frontier, but they've found a way to drill through it. (Cue MusicalSting.)
* In ''TheThirteenthFloor'' the world has no physical wall around it but it does have an edge where the simulated nature is visible to the naked eye. People with in the simulated world are just programmed to never think about going anywhere near that edge (of course there are exceptions...)
* ''[[Film/{{Monsters2010}} Monsters (2010)]]'' has a huge wall being built at the Mexican border to prevent giant aliens from entering the US, though it's proving not to be very successful. Those living in the Infected Zone joke that the giant wall erected around them by the US government will eventually be built around the world.
[[/folder]]

[[folder:Literature]]
* The impenetrable FAYZ Wall which surrounds the area in ''Literature/{{Gone}}''.
* The TropeNamer is a short story by Theodore R. Cogswell in which it separated a magic-dominated half of the world with a science-dominated one.
* The one located in the town of Wall in NeilGaiman's ''Literature/{{Stardust}}''.
* In ''TheSwordOfTruth'' / ''LegendOfTheSeeker'', there is a (almost impenetrable) great barrier around a region called "The Midlands", which is the central geography of the story.
** That barrier is also re-used in ''Naked Empire'' of the same series, to close off a group of people from the rest of the world.
* There's one of these in Creator/GarthNix's ''Literature/OldKingdom'' books, separating the nonmagical land of Ancelstierre from the Old Kingdom, where there's necromancy and other magic. It's actually an artefact containing one of the five {{Cosmic Keystone}}s that keeps [[FunctionalMagic the Charter]] together and is designed to keep anything nasty inside the Old Kingdom where people know how to deal with it. It's only moderately successful, hence the massive trench and bunker network on the Ancelstierran side.
* IanMcDonald's ''Out on Blue Six''--the city is surrounded by a giant Wall, and the protagonists explore to see what's on the other side. [[spoiler: Turns out--nothing but toxic waste.]]
* In Creator/DamonKnight's ''Hell's Pavement,'' people in Connecticut (200 years in the future) know nothing of the people in New York, who know nothing of the people in Ohio, and so on. They believe people in the other places are literally monstrous and inhuman. (There are walls between zones.) This happened because supermarket chains used brilliant new brainwashing techniques to make people totally loyal to their brands, and the adherents of different brands formed different zones.
* ''Literature/TheHitchhikersGuideToTheGalaxy''
** The planet Krikkit in ''Literature/LifeTheUniverseAndEverything'' was surrounded by a thick fog such that they never saw outside their world. [[spoiler:This was done by the remnants of the supercomputer Hactar, making the Krikkiters into an OmnicidalManiac race once they saw the universe. He did this so they would use the universe-destroying bomb he had invented, thus fulfilling a duty he welched on long ago and geting rid of his long-standing guilt.]]
** In ''Literature/SoLongAndThanksForAllTheFish'', Wonko the Sane builds an inside-out house he calls "the Asylum" to fence in the rest of the world (he, naturally, lives "outside the Asylum", which is inside the house). He'd decided [[WorldGoneMad the entire world had gone insane]] when he came upon a pack of toothpicks with ''[[ViewersAreMorons instructions]]''.
* In the novel ''HardBoiledWonderlandAndTheEndOfTheWorld'', the End of the World sections take place in a town which has a wall around it, and once you come to the town you can't go outside the wall.
* If you only follow the first book, [[Literature/LandOfOz Oz]] would seem rather like this. The endless deadly desert surrounds Oz on all sides, isolating it rather nicely. Too bad later books place other magical kingdoms on the other side of a desert that seems rather more like a moat. Eventually, all the magic-users in Oz gather their power to put a wall of invisibility, thus more permanently sealing off Oz.
* There's a short story by Arthur C. Clarke called "The Wall of Darkness" about a planet with a wall that divides it in half. The protagonist attempts to climb the wall too what's on the other side. [[spoiler:turns out there is no other side, and the planet is essentially a 3D moebius strip, and so only has one side]]
* The Void in PeterFHamilton's ''VoidTrilogy'', arguably.
* A global glacier surrounds the only habitable continent on all of {{Darkover}}, literally called The Wall Around the World by the inhabitants.
* In ''Literature/TheSingerOfAllSongs'', the order of priestesses known as the Daughters of Taris live surrounded by a giant wall of ice. They are the only people who can use ice magic, so they control who can come in and out.
* The great Agatean Wall in ''Discworld/InterestingTimes'' in more to keep everyone inside, rather than other people out. According to the leaders, there is nothing but ghost and vampire filled wasteland outside it.
* In ''Literature/TheDosadiExperiment'' the whole planet is encased inside "God Wall" [[DeflectorShields barrier]] as a part of said experiment. Not that it's ''completely'' impassable, but for [[TheMasquerade most people]] inside it is.
* The Land of Elyon, a children's series by Patrick Carman, has walls surrounding the inhabited cities and the roads that link them. The main character finds a way out of the walls, despite the fear of many of the other characters about what is beyond the walls.
* The Green Wall in Yevgeni Zamyatin's ''Literature/{{We}}'', separating the civilization of the One State from the forests around it, which in turn separate them from the rest of the world. We are given few and conflicting clues as to what actually may exist beyond the forest.
* Ted Chiang's "Tower of Babylon" is a speculative fiction short story where it's more of a ceiling [[spoiler: or floor]]. The vault of heaven is a literal stone roof to the universe, and the Babylonians have built a tower to talk to God, who they believe resides above it. [[spoiler: One of them makes it, only to emerge from a cavern deep in the Earth, back where he started--somewhat similar to the Clarke example above, the world loops back on itself.]]
* Marlen Haushofer's "The Wall" is about a woman one day waking up in a mountain valley with the whole valley suddenly surrounded by an invisible, impenetrable wall. With all life outside the wall apparently dead, the book deals with her trying to survive inside the valley. Wondering if she is the last human alive, she speculates about the origin of the wall, [[spoiler: which in the end is never revealed. She often thinks about trying to leave the valley, but never can't bring herself to risk it. What happens with her in the end is left open to the reader.]]
* ''Literature/PerryRhodan'' uses this on a number of occasions (including a 'wall' around the entire ''Milky Way Galaxy'' that the protagonists had to deal with after losing a few hundred years in an unexpected stasis field while outside, once). There's also a more literal example in Wardall, a tide-locked planet with a wall running around its entire circumference following the terminator. The planet's former natives apparently lived ''inside'' said wall rather than on either side of it, not surprising considering the conditions there; by the time the issue set on the world opens, though, its only inhabitants are the surviving crew members of a crashed pirate vessel and their descendants.
* The wall separating Experiment House property from Narnia in ''TheSilverChair.''
* A literal example is the spherical Walls of the World from Creator/JRRTolkien's legendarium, which are only specifically described in ''Literature/TheHistoryOfMiddleEarth'' although their existence is implied in ''TheSilmarillion''. The walls separate the world from the empty void of the Outer Dark, and are only pierced by a single Door of Night, created by the Valar to thrust [[BigBad Morgoth]] out until TheEndOfTheWorldAsWeKnowIt.
* A large portion of the plot in Orson Scott Card's ''Literature/{{Pathfinder}}'' revolves around one of these. It's revealed decently early on that there are actually 19 "worlds" with Walls.
* In ''Literature/TheLegendsOfEthshar'', the world of Ethshar is a FlatWorld, being the end-cap of a cylinder. The edge of the end-cap is marked by a "noxious yellow gas".
* The wall (or "Barrier") in Lee Arthur Chane's ''Magebane'' was created long ago by mages as a defense against a [[WhatMeasureIsANonSuper commoner uprising]]. It's assumed that it will last for another two hundred years. [[TheMagicGoesAway This is a bit of an overestimate]].
* There aren't any literal walls in ''CityOfEmber'', but there might as well be -- the only light comes from the city, as does all of the food and other necessities, making it impossible to leave. Nobody in the city knows what might exist outside of it, if there's anything there at all. [[spoiler:It turns out that the entire city is actually underground. The original builders included instructions for leaving the city to be used after a certain amount of time had passed, but they were lost and forgotten before they could be used, leaving the citizens trapped in a city with dwindling food and power supplies, and no way of knowing that escape was necessary or possible.]]
* In ''Literature/ASongOfIceAndFire'', Westeros has a massive (as in 800 foot-high) wall built of ice blocks in the far north, stretching from the continent's east coast to the west. The Wall was built to keep out the [[EldritchAbomination Others]], evil ice beings, and is manned by the Night's Watch. The Wall is so old that most people have forgotten all about the stuff that lives behind it, but they're unpleasantly reminded when [[spoiler: the Wildlings attack, [[OhCrap followed by the Others]]]].
[[/folder]]

[[folder:Live Action TV]]
* The [[{{Two-DSpace}} barrier around]] [[SciFiWritersHaveNoSenseOfScale the galaxy]] in the ''Series/StarTrekTheOriginalSeries'' episode "Where No Man Has Gone Before".
** Another old series show, "For the World Is Hollow and I Have Touched the Sky", where the world is a hollow asteroid.
* In the ''Series/DoctorWho'' story "Inferno", the Doctor pushes through a barrier in time and ends up in a MirrorUniverse.
** Also used in the ''[[Magazine/DoctorWhoMagazine DWM]]'' comics, most notably in "Oblivion".
* On ''ThePrisoner'', the mysterious Village is surrounded by unclimbable mountains to the north, and the sea to the south. On several occasions, the eponymous Prisoner attempts to escape by boat, but he always ends up getting caught.
[[/folder]]

[[folder:Music]]
* Music/PinkFloyd's ''Music/TheWall'', which isolates the protagonist from... the world in general, but especially his fans.
[[/folder]]

[[folder:Myth, Religion, and Legend]]
* Jericho, from ''Literature/TheBible'', is now synonymous with its absurdly strong fortifications. Tends to happen when it takes ''God Himself'' to bring them down.
** There is also reference to a the sky being a firmament, a literal wall around the entire world. This is slightly different than the usual application of this trope, as there is pretty much nothing outside of the area enclosed by the firmament, which exists to hold back the waters that are the source of rain. Although the Book of Isaiah does describe Yahweh as having his throne on top of the firmament.
* A pre-Islamic Turkic myth has the Turkic people fleeing into a valley surrounded by mountains of iron to survive an onslaught. Their point of entry collapses, effectively sealing them from their enemies and letting them stay there for generations. When they decide to leave, they do so by ''melting'' the iron mountain.
[[/folder]]

[[folder:Tabletop Games]]
* The borders between the physical realm and the spirit worlds in the ''TabletopGame/OldWorldOfDarkness'' RPG line (the Gauntlet and the Shroud) qualify. Most humans have no idea that the spirit realms are real.
** The Gauntlet still stands in the TabletopGame/NewWorldOfDarkness, cutting off the Shadow from the material. There's also the Abyss, which severs the Supernal from the Fallen.
* TabletopGame/DungeonsAndDragons, [[{{Troperiffic}} as always]]:
** The Misty Border in the ''{{Ravenloft}}'' setting cuts it off from the rest of the multiverse. You can check in, but you never check out. Darklords can do this at will (with few thematically-appropriate exceptions) to isolate their own domains.
*** The town of Barovia has its own permanent version of its domain's closed border; only the Vistani know how to make a secret antidote that allows safe passage.
** ''TabletopGame/{{Spelljammer}}'' has a borderline case: crystal shells. Oh, it can have many thousands of portals... spread over the whole surface of a ''star system'', that is. It's not easy to find one without knowing where it is, and they don't always stand still forever. Thus the proper magic is the best way to locate a portal or even open temporary one -- for those who have it.
* The Weirding Wall in ''TabletopGame/{{Nobilis}}'' which encloses the whole universe.
* ''TabletopGame/{{Paranoia}}'' is set in Alpha Complex, a domed city. The existence of "Outdoors Sector" is acknowledged, but information about it is limited, especially at low security clearances.
[[/folder]]

[[folder:Video Games]]
* ''VideoGame/CustomRobo'' (the Gamecube version) has the humans live inside a domed city that isolates them from the post-apocalyptic world. The outside world is kept secret except to a select few. But [[spoiler: when you beat Rahu III, the final boss, it is revealed to everyone]].
* In ''VideoGame/{{Grandia}}'', an entire continent was divided by an enormous wall about a mile high. No one ever tried to explain ''why''.
** Could have something to do with [[EldritchAbomination Gaia]] [[TakenForGranite killing]] [[FateWorseThanDeath almost]] [[RealityWarper everything]] in its path, as it's only encountered on that side of the wall until it got on an airship.
** ''VideoGame/GrandiaII'' had something similar, a huge nigh-uncrossable canyon, though its existence was explained: it was basically caused by God crashing into the earth.
* In ''VideoGame/{{Wild ARMs 4}}'', your first indication that Ciel is not a typical RPG hamlet is when fighter craft shatter the barrier surrounding it that was disguised as sky. The outside world is quite a bit different.
* ''CityOfHeroes'' has the War Walls, [[JustifiedTrope justified]] as barrier against alien invasion, but really there as a level separation.
* Palm Brinks in ''VideoGame/DarkCloud 2'' was [[CityInABottle sealed off from the rest of the world]] via a titanic wall, far too tall to scale. This was done by the Mayor, to protect the citizens from the incredible devastation taking place in the outside world --but now that the land is healing (and with the heroes having escaped via an underground sewer/aqueduct,) many of Palm Brink's inhabitants dream of exploring and building new cities.
* ''StarControl 2'' has slave shields -- barriers around homeworlds of defeated races who don't want to fight on Ur-Quan side.
* ''VideoGame/TheLegendOfZeldaTheWindWaker'': The Great Sea has no physical barrier to keep you from leaving the map. However, your boat tells you that it's dangerous to leave and turns you around.
** ''VideoGame/TheLegendOfZeldaSkywardSword'' has an impenetrable cloud cover that separates the residents of Skyloft from the surface. As far as the people of Skyloft are concerned, the "surface" is a mythical place, rumored to be filled with monsters.
* Gensokyo, the setting of the ''VideoGame/{{Touhou}}'' games, is walled off from the Outside World by the Great Hakurei Barrier [[FantasticNatureReserve to preserve]] {{Youkai}}, though people and objects occasionally slip through (particularly things the outside world has stopped believing in).
* There's no actual wall on Hillys in VideoGame/BeyondGoodAndEvil, but if the player strays too close to the edge of the map, a series of pillars will rise up out of the water and warn the player that they're leaving territorial waters. Trying to get past them will just lead to them shooting non-lethal lasers at the player's vehicle to turn it around.
* ''{{Lusternia}}'' is comprised of the Basin of Life, which is entirely isolated from the rest of the world by mountains. Nobody can get out, but there have been cases where denizens have come in from/gone out to some place on the outside.
* In ''VideoGame/{{Fallout 3}}'', Vault 101 was intended to never open its door. The line is, "No one ever enters, and no one ever leaves." [[spoiler:[[SubvertedTrope Neither are true]]: your dad is from Rivet City, and you and he both leave.]]
[[/folder]]

[[folder:Webcomics]]
* The area known as The States in ''WhiteNoise'' is surrounded by a gigantic wall and poison gas filled moat. No one is allowed in or out except for bounty hunters, and residents hate and fear those who live beyond it.
* In ''Webcomic/SluggyFreelance'' the "Punyverse" turned out to be surrounded by a giant solid sphere, the inhabitants mostly didn't know that and thought it was an endless void inhabited by "void ghosts" that occasionally attacked (it was really wild shots reflecting off the sphere). Also [[spoiler: their entire universe was artificial]]
[[/folder]]

[[folder:Web Original]]
* Our whole ''universe'' in ''FineStructure'' is 'walled'. Nothing gets in or out. [[spoiler: It's actually a prison designed to keep Oul inside.]]
[[/folder]]

[[folder:Western Animation]]
* ''WesternAnimation/TheSimpsons''
** The school is split into the clean, cutesy "girls" side and the rough, rowdy "boys" side.
** Also, the glass dome enclosing Springfield in TheMovie.
** And the wall made of garbage separating Springfield from New Springfield.
* In ''WesternAnimation/{{Futurama}}'', the Planet Express crew visits the Edge of the Universe, which has a convenient viewing platform. They are able to look through binoculars at the Universe Next Door, (which is apparently cowboy-themed).
-->''Fry:'' Wow. So there's an infinite number of parallel universes?
-->''Professor Farnsworth:'' No, just the two.
* In ''WesternAnimation/SouthPark'' episode "Pinewood Derby", [[spoiler:Earth and the Moon are sealed off by a cube-shaped force field after the humans fail the Space Cash Test]].
** Also, in the episode ''Child Abduction is Not Funny'', the paranoid parents in South Park had Mr. Lu Kim build a huge wall around the town to keep kidnappers out. It was ordered to be demolished again at the end of the episode.
* The ''{{Duckman}}'' episode ''Exile in Guyville'' had a wall being built down the middle of America, dividing the sexes with Women on the East and Men on the West.
* Ba Sing Se, the Earth Kingdom capital in ''WesternAnimation/AvatarTheLastAirbender'', is surrounded by two giant walls. People within the city are generally encouraged not to even ''think'' about the world outside the walls.
* ''PhineasAndFerb'': in "Escape from Phineas Tower", the titular tower traps Phineas and Ferb and their friends in a dome. To escape, they make the tower realize they have friends in multiple places, causing the tower to encast larger and larger areas into its dome, untill eventually the dome ends up surrounding the entire milky way galaxy.
* ''FairlyOddParents'': episode ''Love Struck'', Timmy wishes for the worlds population to be divided by gender, causing the Earth to be split up in a men's half and a womans half, seperated by a large wall circumnavigating the Earth at the poles.
[[/folder]]

[[folder:Real Life]]
* The closest we got to a wall separating the ''entire'' world was during the ColdWar, with the famous Iron Curtain.
[[/folder]]
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