Flat World

If you walk far enough, you'll fall off the edge of the world. For this world is not round, but flat. What lies beyond the edge? No one knows.

In ancient history, many cultures believed the Earth was flat. Certainly the curvature is so slight that it wasn't until the Greeks that the spherical Earth theory took hold (contrary to popular belief, Columbus didn't have to try and convince people that the earth was round).

Flat worlds typically only appear in fantasy. They will usually be a circular disc, although other shapes have appeared. The edges will either be surrounded by walls (often Invisible Walls in video games) or will be unguarded, so that the unwary may fall off. Occasionally, there are no edges - the world goes on in all directions for infinity.

Sadly, some people believe that this is Truth in Television. Less literally, the trope was considered to be truth in television in practice, up until World War 2, and Pearl Harbor was often treated as the edge of the world by both the Japanese and the Americans.

A subtrope of Bizarre World Shapes.

Not be confused with an animation called Flatworld.

Anime & Manga

 * The Digital World in Digimon Tamers consisted of seven discs stacked one on top of another.

Comic Books

 * The Godwheel in the cancelled Ultraverse comics 'verse is an Alderson disc: a flat disc billions of kilometres across with a star in a hole in the middle, on which multiple ecosystems evolved in widely separated regions. All the alien species that visit Earth originate from this single world.

Film

 * The animated movie Sinbad: Legend of the Seven Seas. "Pay up, it's flat."
 * The Terry Gilliam short film The Crimson Permanent Assurance, released alongside Monty Python's Meaning Of Life, is set on a flat world. It also has elderly accountant pirates who . Really, by the time it comes, nothing could make more sense.
 * Some of the characters in The Gods Must Be Crazy think they are living on a flat world, and undertake a quest to throw an object off the edge of it to get rid of it. Since it's earth, viewers might be inclined to smile knowingly at this, but...
 * In Eric the Viking, the characters.
 * This partially averts the usual Flat Error (that "back then everyone thought the world was flat"). The token Christian DISbelieves in the edge of the world.
 * Pirates of the Caribbean has this in the third movie. Beyond the edge of the world is the entrance to Davy Jones Locker. A rather strange case, since you apparently can't just pick a direction and sail there until you reach the end, because then anybody could get there. You have to be truly lost at sea, and then you magically teleport to the end. So, it's debatable if the world is flat in this universe, or if it's round, and you just get transport to a strange waterfall place when you're lost.
 * In Dark City,  is a very tiny world like this.

Literature

 * The Discworld, as its name suggests, is a very slightly convex disc. It's also supported by four giant elephants on the back of an insanely vast turtle. It has a (spherical) tiny sun and a tiny moon, which travel in complex patterns to make seasons. (Sometimes, one of the elephants has to cock a leg to let them go by.) In fact, one novel concerns the bold efforts of religious fanatics who believe the world is round because God prefers perfect circles going about crushing dissent from any scientist who tries to prove the world is actually flat. Which it is.
 * In Going Postal, Lord Vetinari says that 1000 years ago people thought the world was bowl-shaped, and 500 years ago the Omnian globe idea was mainstream.
 * The Moon at least, as shown in The Last Hero, is a globe shape.
 * There's also Terry Pratchett's earlier novel Strata, which has an (artificially constructed) flat world with an orbiting sun designed to look like a Ptolemaian world map.
 * Narnia is also flat. The characters reach the edge in Voyage of the Dawn Treader. The 3 children never do see what (if anything) lies beyond Aslan's Country (though it's implied that the dome of the sky comes down to meet the ground there). The Narnians are surprised to find out that the Pevensies come from a round world, and are delighted, because that's what their fantasy stories are about.
 * In the Silmarillion, it's revealed that Arda was originally flat. It was reshaped into a sphere by Eru Iluvatar to prevent humanity from attempting to sail to Valinor.
 * In earlier versions of the cosmology, Arda was actually a cross between a flat world and a hovering world: Arda was literally shaped like a boat, solid earth cupped to hold the "inner seas" with the continents and islands of the world rising up from its floor. The world floated upon the "outer seas" ("Vaiya", which was in turn split between a shadowy "water" that no mortal ship could float upon and a tenuous "air", both so cold as to freeze the inner seas where they meet), which were in turn vaguely separated by the boundary between the universe (Ea) and the sea-like "void" leading to the Timeless Halls where Eru Iluvatar resides. Even stranger yet, the sky was a literal pennant-like sail, attached to Arda by the mast like peaks of two inconceivably tall mountains. The sun and moon dipped into the seas of the vaiya in order to go underneath the "keel" of the world, and the sea god Ulmo actually had a residence built onto the bottom of the world like a barnacle on the hull of a ship.
 * The novels Circumpolar! and Countersolar! feature an alternate Solar System in which every planet and moon is a holed disc (but the Sun is still a spheroid). Earth's familiar continents are wrapped around the North Hole, with Antarctica stretched around the rim, and the first novel concerns a pair of rival expeditions to the unknown other side of the world.
 * Flatland, which is not merely flat but two-dimensional, inhabited by squares, triangles, circles, and the like. There is air and rain but no mention of any actual ground...
 * Subverted in Sphereland, a follow-up to Flatland, wherein the narrator discovers that by a combination of circumnavigating the world and showing that sufficiently large triangles have interior angles that add up to more than 180 degrees. Naturally, he's disregarded as a heretic.
 * In Flatterland a world is discovered that is a circular disk of finite size and infinite area. In the middle things are "normal" size and as you move toward the edge everything gets smaller, preventing anyone from ever reaching the edge.
 * Dewdney's novel The Planiverse goes further, positing an entire 2-dimensional universe with its own physics, chemistry, and biology. Circular planets orbit circular suns, and life exists on the "surfaces" (i.e. circumferences) of those circular planets. Some of these life forms even build 2-dimensional houses for themselves.
 * Pyramid Scheme, despite its title, features the flat world of Greek mythology -- Europe and northern Africa, girdled by the River Ocean.
 * The novella Missile Gap by Charles Stross takes place on an Alderson disc big enough that have been flattened and placed on it.
 * The world of The Neverending Story is apparently flat, and goes on forever in all directions.
 * In The Deerslayer (the prequel to Last of the Mohicans), Hawkeye tries to convince his Noble Savage friends that the world is round, but they don't buy his arguments, since they can see the sun rise and set each day.
 * Philip José Farmer's Alternate History short story " " turns out to be the grimly amusing story of how
 * Not to mention his Tier World, which consists of several flat tiers stacked one onto another. Some Mooks even end up fallen off the edge.
 * HP Lovecraft's Dreamland is apparently flat, or at least there is one place where you can sail off the edge of the world and "fall" into space.
 * Technically, the landscape of the Ring World is a Flatworld, as it only has one side and has edges walled off with hundred-thousand-mile high walls.
 * The poem "The Edge of the World", by Shel Silverstein.
 * The illustration on the cover of the book Where The Sidewalk Ends uses the illustration from the poem "The Edge of the World", leading some to mistake the illustration to be for the specific poem "Where the Sidewalk Ends" (Which is actually about the grassy area between the sidewalk and the street).
 * The world of Ethshar is the flat end-cap of a cylinder, surrounded on all sides by a yellow gas.

Tabletop Games

 * Among the several extradimensional worlds invading Earth in the Tabletop RPG TORG is the High Fantasy realm of Aysle, an Earth-sized discworld with life on both sides and a hole in the center through which a small sun rises and sets.
 * The world of Creation in Exalted is flat. It's regulated by the four Elemental Poles in each direction (Air in the North, Water in the West, Fire in the South, and Wood in the East), as well as the Elemental Pole of Earth in the center. Beyond the world is the Wyld, a realm of ever-changing, pure formless chaos. And the sun? It's the light-giving avatar of the king of the gods. The stars, planets and moon are also such representations.
 * Before the Primordial War, Creation did have a defined boundary, in the form of an enormous river (one of the bodies of one of the Primordials).
 * A Polish parody RPG called Nieboraki has described the world as flat and lying down on a table.
 * Magic the Gathering has Rath, a flat world which is "vibrating" on a different frequency than Dominaria. As Rath gets larger, its vibrations slow until it vibrates in sync with Dominaria. The whole plane exists so the Phyrexians can take over.

Video Games

 * Grandia had an interesting variation. The world was formerly believed to be round, as revealed if you examine a globe in the obligatory ghost ship; however, shortly before the game begins, the end of the world is found, and thus the world is believed to be flat.
 * In the Might and Magic series of games, one world, Xeen, is flat. One quest involves uniting the two halves. The player cannot fall off the edge, but can teleport to the nothingness and promptly die.
 * The planet Albia in the Creatures games is a disc-shaped world- but life only occurs on the outer edge, so essentially this combines a disc-shaped and a ring-shaped world. (It doesn't encircle its sun like the other ring-worlds on this page.) The discovery by the Shee that most planets are round is a plot point.
 * Evidently, the faces would be able to support life, if not for the fact that while the planet itself is disc-shaped the gravitational pull acts as though it were spherical, so if you tried to stand on the faces, you'd discover that the gravity pulls you towards the hub and slightly presses you against the face itself, so the net effect is akin to holding your enemy against a passing train in a subway station.
 * As is the world on which the Golden Sun games take place, complete with the oceans constantly spilling an apparently infinite amount of water over the edges. Interestingly enough, the dangers inherent in such a system are actually brought to light in the second game.
 * In Golden Sun Dark Dawn, which takes place 30 years after the end of the Game Boy Advance duology, the world's oceans and continents are now separated into layers, with the heroes' ship being unable to reach any continents other than their own due to the other continents being separated by waterfalls. Other than the addition of layers, the world is still a flat one but may revert back to its original shape in the years down the road since there's still natural activity happening in the world in the 30 year gap.
 * Some of the planets in both Super Mario Galaxy and Super Mario Galaxy 2 resemble these, with optional black holes underneath. If you fall off the planet and into the black hole, you die. And if there isn't a black hole and you fall off, you still die.
 * Played straight in the Burning Crusade expansion of World of Warcraft. The world of Outland is considered to be the largest fragment of a shattered world, and players in the game can fall off the edge and die (dying in such a way causes you to be resurrected at the nearest graveyard from the point you fell off)
 * Minecraft has an option that lets you play a world that is literally flat, being made up of nothing but grass, two layers of dirt, and bedrock right below it. The main purpose of playing on a flat world is to assist in players that wish to build something without having to terraform the landscape.

Webcomics

 * Rice Boy and Order of Tales both take place on Overside, the top half of a flat world. Travel between the two sides was possible in the past, though it is now restricted, but.
 * Unicorn Jelly has Tryslmaistan, a universe where all worlds are flat triangular plates of extremely regular shape and size, justified due to having different laws of physics than our world. Each worldplate also has its own greater and lesser light source in a complex orbit, a "sun" and "moon". Since only objects of worldplate size are suspended against the omnipresent unidirectional "gravity", any time a plate breaks up or wears down too small, it falls, breaking others until Tryslmaistan is consumed in a "stormfall" of matter that eventually spreads throughout the entire universe (wrapping all the way around the universe's finite but unbounded vertical plane and likewise expanding horizontally until it meets itself). Then the debris is eventually clumped into triangular shapes by the natural forces of that world, and it all starts over again. Its sequel, Pastel Defender Heliotrope, takes place in Pastel, a similar universe of rectangular worldplates.
 * One Xkcd strip has a character stranded in an infinite desert for an infinite period of time, alone and with no way out, unrestricted by physiological needs like food or water. His arranging of pebbles on the plane is a particle-by-particle simulation, of our universe.
 * Our Little Adventure takes place on the plane of Manjulias, which is flat.
 * The world in Vanadys Tales of a Fallen Goddess is not only flat, but also broken into two separate pieces, thanks to the actions of the titular fallen goddess.

Web Original

 * The titular world of Elcenia is a ten mile thick square. Elcenia is somewhat unusual in that you can walk over the edge, but not fall off: "Gravity" just abruptly changes direction and you can continue walking down the side of the world, or even across the underside.
 * Pandora, from the Dominion and Duchy canon is a flat world that is somewhat unique in that it exists, possibly naturally, in a space opera setting.
 * In part 4 of The Sick Kids, the sequel to The Intercontinental Union of Disgusting Characters, we learn that Central Earth is flat. ("What did you think it was anyway, round? Hah, we'd all fall off then!")
 * The world of Minecraft is flat and practically endless.
 * The International Square Earth Society is an extremely deadpan parody of flat-earthers. It uses Bible verses to prove that the Earth is not only flat, it's square like a saltine cracker.

Real Life

 * The idea of everyone thinking the world was flat wasn't universal. Through history some people thought it was flat, some thought it may be round, but for the most part people probably didn't worry themselves about it much. While many people cite the idea that when a ship sailed to sea the mast was the last thing to disappear to the observer, the problem is that by the time a ship is that far out at sea (several miles for a 5.5-foot-tall person), the ship is so small to the unaided eye it's hard to make out the mast - and telescopes weren't developed until 1608 - a time when the fact that the Earth was round had been proven practically.
 * The first mention of a spherical Earth in history was the Greeks in the 6th century BC, but that doesn't mean the idea hadn't been batted around already.
 * The first person recorded to measure the circumference was Eratosthenes in 240 BC. Using the angles of shadows at noon he was within a 2%-20% margin - pretty good for what he had to work with.
 * By the time of Columbus (1492) the earth was understood to be round by most educated people. There was less fear of Columbus sailing off the edge of the earth than the simple fact that it was uncharted waters he was sailing into, and no one knew when/if he would run into land. Also, Columbus had far underestimated the actual size of the Earth, and combined that with the largest estimation of how far Asia stretched eastward to conclude that the distance from Europe to Asia westward was only about 2,500 miles (in reality, it's closer to 15,000 miles). See analysis by Samuel Eliot Morison in ADMIRAL OF THE OCEAN SEA.
 * The fact that the earth was round was finally proven practically with Ferdinand Magellan's circumnavigation of the globe, starting in 1519.