Here There Be Dragons

"Scully: On the old mariner maps, the cartographers would designate unexplored territories by simply writing "Here Be Monsters".

Mulder: I've seen the same thing on maps of New York City."

- The X Files, "Quagmire"

In old times, mapmaking was a fairly imprecise task, due to the lack of advanced technology for exploration purposes. So, to fill great blank areas on the maps, mapmakers used to include textual and/or graphic warnings of the dangers of going into uncharted territory. Such warnings took the form of sea serpents, dragons, cannibals and many other mythical and, sometimes, even real creatures. The actual line "Here There Be Dragons" has been found only once, on the 16th-century Lenox Globe -- but is too cool to give up.

This tendency is explored in fiction with two usual objectives. The first and more obvious is to show that the map is very ancient or simply medieval. Depending on the setting, the map may be contemporary, but displayed in an outdated manner because that's how things still are made.

The other use of this trope is to avoid showing the viewer a dull and realistic map. This is mostly used in video games, to give the World Map a more enjoyable presentation.

In fiction, many maps don't just warn its readers of the great perils on their way, but sometimes also contain other pieces of information, such as the location of cities and landmarks, pointed by stylistically out-of-scale drawings.

Because Everythings Better in Latin, also sometimes seen as Hic sunt dracones.

Do not mistake this with Here There Were Dragons, which is about the existance of magic (and even dragons) sometime in the past of the setting of a fictional work.

Anime and Manga

 * Skypiea's map in One Piece had several symbols, including a ziggurat (marking the position of ) and some devilish creature roaming through the land.
 * The Magic World's map in "Mahou Sensei Negima!" has 'here be magical creatures' in chapter 190.

Film

 * How to Train Your Dragon has a map with, wouldn't you know it, dragons. This is meant literally, as it signals the dragon's nest.
 * In Pirates of the Caribbean, during Barbossa and Jack's swordfight, Barbossa gloats over Jack having gotten in way over his head (by, y'know, engaging in single combat with an immortal), taunting him by saying "You're off the edge of the map, matey. Here there be monsters!"
 * Jackboots On Whitehall. The excessive detail of the map of Britain stops abruptly at the Scottish border, which shows no towns or roads at all.
 * The credits of Cars 2 did this with submarines, which appear to serve as stand-ins for whales.

Literature

 * The map in The Hobbit depicts the location of Smaug's Lair with the drawing of a dragon, and spiders on the Dark Forest. It also has an arrow pointing off the edge of the plotted area, noting that to the north lies a terrible wasteland "whence came the Great Wyrms".
 * Parodied in Discworld, where tourists' maps of Anhk-Morpork are labelled "Here Be Dragons" to mark the location of the Sunshine Sanctuary For Sick Dragons, a veterinary hospital. The same phrase appears over the actual Sanctuary's entrance as grafitti.
 * Elsewhere in Discworld we're told that cartographers sometimes got so carried away with drawing sea monsters that they forgot to put the boring countries and so on in at all.
 * In a rather wonderful moment in The High Crusade, the narrator (a Medieval monk) criticizes a technologically advanced alien map. Sure, it might be accurate, but its lack of dragons, mermaids, sea serpents and such ornamentation shows a poverty of cultural imagination and depth.
 * Gathering Blue had this.
 * Discussed in the Lord Peter Wimsey story "The Learned Adventure of the Dragon's Head". One of the things that arouses Lord Peter's suspicion of the villain is that he claims to have seen "hic dracones" on the maps in a mediaeval book. Lord Peter, being an actual book collector, knows how unlikely this is.
 * Throughout the Star Wars Expanded Universe novel Crosscurrent The Hero Jaden Korr uses "There be Dragons...”, when thinking about his doubts about himself, the force, and everything.

Live Action TV

 * On Head of the Class Billy Connolly referenced this in the context of showing off the new world maps the school bought - he said the other ones were so old they had "Here dragons be" indicators.

Tabletop Games

 * Warhammer marks its map of the northlands and southern wastes 'Here There Be Daemons'. They're right.
 * Warhammer40000 has space monsters on its star charts. Again, they're right.

The Other Wiki

 * An article on the subject with plenty of both Real Life and fictional examples.

Video Games

 * Wario Land: The Shake Dimension had one of these maps. Note the mermaid, sea serpent and octopus-like creature in various points on the map and the old-fashioned compass (itself something many of these maps also contain).
 * The Map of Tibia.
 * Fanciful illustrations can be found on the in-game Arcanum world map, in keeping with the setting. Most of these pictures are of animals not found in that locale, or at all, but at least one provides a little hint of what you'll find there.
 * Eternal Darkness had the actual line "Here Be Dragons" on a globe in the observatory.
 * An Easter Egg in Grand Theft Auto Chinatown Wars references the trope: swim out to any of the four corner of the game map, and you'll find a sign with old-script telling you that "Here Be Dragons", which is as good a Hand Wave as any for why you can't get away from Liberty City.
 * In Return to Ravenhearst, the schoolroom where Rose's daughters were indoctrinated by Charles Dalimar has a crude outline of England and Wales on its wall map, in which everything else is blank and marked "unknown". No actual monsters are depicted, but the creepiness of the script implies that horrible things lurk beyond the borders.
 * In Risen while there's no mention on the map, if you go out too far into the sea, a giant sea monster bursts out of the water and eats you. Humorously, you'll wake up on the beach a bit later without any harm. Observe here.
 * In the intro to the original Colonization your colony ship sails across one of these, encountering various sea serpents and anthropomorphic storm clouds as it goes.

Web Original

 * Political sketches: This map.
 * Freemans Mind: In one episode Gordon Freeman encounters an utterly useless map and mocks it by using this trope:

"Freeman: Oh sweet a map! Ok so where am I ... which way's North? Maintenance shaft ... that .. could be anything; half this building is a maintenance shaft. What's that big room, is that where the monster is? What about this radiation pit? High voltage ... that has to be where I came from. But what the hell is with these distances then? Why are parts of this map grayed out? Is it haunted? WHY IS THERE NO EXIT ON THIS MAP? Is there a landmark ...? This map is bullshit; I'm gonna find my own way out of here. That map has to be bogus; it only lists one area as being dangerous. It needs to have, like, 30. You could even write "Here be dragons" on it, and it would almost be more accurate than nothing at all."

Webcomics

 * Xkcd Map of Online Communities "Here be anthromorphic dragons"
 * This Wapsi Square strip.
 * Yet Another Fantasy Gamer Comic has, according to an old tome, "a deadly labyrinth filled with creatures most foul". Given that the members of this specific party were drow, half-orc, hobgoblin, minotaur and illithid, their reaction was... rather predictable.

Western Animation

 * The Simpsons: In an episode where Homer went on a sea voyage, it was montaged by a dotted line traveling across such a map. He crashed into the compass, and avoided the sea serpent outright.
 * One Disney-themed map of the world did this with characters from The Little Mermaid.

Real Life

 * In a sense the Universe runs in this trope. It's so inmense that, despite we've send probes to all the planets of the Solar System and the extensive surveys done with telescopes, can be considered uncharted -to give one example in our Solar System, it's still unclear if the Oort cloud exists or not-. We may know many stars have planets, but until the day we can go to that planets (if that day arrives) it's impossible to know what could be waiting for us there. Same to a larguer extent for the other hundreds of billions of stars that compose our galaxy, to say nothing of other galaxies.
 * Other astronomical example could be the Zone of Avoidance of the Milky Way, at least until became possible to study that area of the sky with in other wavelenghts (infrared, radio, X-Ray...) that weren't so affected by the interstellar dust as the visible light.