Leela:"Uh, Professor, are we even allowed in the Forbidden Zone?" Professor Farnsworth:"Why, of course! It's just a name, like the Death Zone or the Zone of No Return. All the Zones have names like that in the Galaxy of Terror."
In Speculative Fiction, there is always at least one area with a foreboding name that nobody goes to. Ever. Whether it's an impassable swamp, an asteroid field, a city rumored to be haunted, a monster-infested mountain passage or simply a place the elders have declared off limits, this is the place everybody knows you only go to when you're insane.
So, naturally, the heroes will inevitably wind up going there — whether by choice or circumstance. What good is having something that's mysteriously off limits if we can't go there and see why it's off limits? Chances are the dangers are completely exaggerated anyway, right?
It will either turn out that the Forbidden Zone is indeed incredibly dangerous, or that there's no danger at all, and the heroes were supposed to keep out because it contains forbidden knowledge. Or both. In either case, the heroes will pass through more or less unscathed, and they may even figure out a way to make the zone less forbidden.
Compare Forbidden Fruit, Schmuck Bait. The dangerous kind of Forbidden Zone overlaps with Death World.
Not to be confused with Forbidden Zone, a Danny Elfman film.
In the Archie Sonic the Hedgehog comics, there was the Zone of Silence, which was that continuity's answer to the Void. However, recent events would turn the Zone of Silence into the Special Zone.
The Pitt, the fifty-mile wide, fifteen-mile deep crater where Pittsburgh, Pennsylvania once was in The New Universe. Made especially notable due to the mutagen-like "Pitt Juice" and the seven mile-high "Mt. Pittsburgh" volcano.
The French comic series Forbidden Zone. The titular zone is a miles-high concrete bunker in Nevada where top secret military research (including aliens, among other things) takes place. A notable gag involved its redundant security systems required to get through (signed permission papers signed by the supervising general, passwords, retinal scans, fingerprinting, anal probing, turning two keys at the same time), revealing that the professor merely forgot a few papers at his desk. The cleaning lady laughs with him about it and sweeps the dust outside, showing for all its secrecy, the professor's office is reachable by a screen door in a low-rent part of town.
ElfQuest has the Forbidden Grove, originally called that by the local humans because people who went in never came out. Turned out this was because the Preservers lived there and spun cocoons around any creature who went to sleep there, putting them into suspended animation.
The island of the Peligostos in Pirates of the Caribbean: Dead Man's Chest. They make the most delicious long pork. Their ride dumps Will overboard to get there.
And then there's the Sixth Dimension in the movie Forbidden Zone. It's special.
Planet of the Apes prominently features a Forbidden Zone, which contains the important information that they were really on Earth the whole time. The area is actually called "The Forbidden Zone" and is also an inhospitable desert, so there's some practical reason beyond the withholding of scientific information. In the Tim Burton remake, the Forbidden Zone is the crash site of the spaceship that originally brought the apes and humans to that planet ages ago, as well as the proof that the humans were their original masters.
The Intrusion Zone in Enki Bilal's Immortal, formerly known as the Central Park, New York. Apart from causing its surroundings to experience perpetual winter, it instantly kills anything mortal attempting to breach its perimeter. The laws of time and space bend at its core, and it's implied to be the origin of the various nonhumans inhabiting the future New York; at least Jill and John arrived the planet through it.
Space Hunter: Adventures in the Forbidden Zone. (In 3-D!)
In The Return of Hanuman, the village of Bajrangpur has a Forbidden Zone behind a large wall. Rumors say that there are demons in there, though it's actually an infamous gang's HQ.
The Dead Marshes and Moria. Also contains a subversion in that the Fellowship attempts to cross the Pass of Caradhras and is forced to turn back and go through Moria instead. Subverted in the films, in that Gimli fully expected Moria to be a safe place still populated by dwarves, indicating that most people (or at least most dwarves) don't know that it's become a Forbidden Zone.
Other Forbidden Zones include the Old Forest, the Barrow-downs, Fangorn and the pass of Cirith Ungol.
Lampshaded in book six, where, when a centaur becomes a teacher and moves out of the forbidden forest into a specially modified room, someone asks why they don't just have class in the forbidden forest, as nobody's even scared of it anymore.
The Wheel of Time features two Forbidden Zones, the Blight and Shadar Logoth, each saturated with evil. Both are entered in the first book, and the latter is revisited repeatedly. Neither is a pleasant place to be. It's a safe bet that anything in the Blight that lives (though "lives" is stretched in some cases) is a deadly threat, and Shadar Logoth is home to the physical manifestation of hate itself. Also, the Ways. You do not want to run into MachinShin.
In Paradise Lost Satan has to pass through the realm of Chaos after leaving the gates of Hell in order to reach Eden. None of the other demons dare to follow, until he comes back triumphant.
The Wax Forest, which is completely overrun by croach Until Tavi awakens its sleeping guardian and nearly destroys the world, although the Marat use it for trials and recover a potent medicinal mushroom from it, generally at a rate of one person retrieving it a year.
Tavi: Why don't you send more people?
Doroga: We do.
The Feverthorn Jungle is a much more mysterious forbidden zone. All that's really known is that it used to be the stronghold of the first sentient species obliterated by Alerans, and also it kills people Whatever is in there apparently kills Vord too, since despite being ideal for growing croach it's never overrun.
In The Last Book in the Universe, the Forbidden Zone (called simply "The Zone" by those who live in Eden) is a minefield which separates the latches (where the normals live) from Eden (where the proovs live). Naturally, the Forbidden Zone is forbidden to normals, but the Zone is not forbidden to proovs.
In C. S. Lewis' Space Trilogy, the entire planet Earth qualifies as a Forbidden Zone to the rest of the Solar System, being known as Thulcandra, The Silent Planet.
Robert Westall's Futuretrack Five has a Forbidden Zone which covers most of the Scottish Highlands. Ostensibly there to protect endangered wildlife, it's really to conceal the activities of the mysterious Scott-Astbury.
In the world of A Song of Ice and Fire there was an ancient empire known as the Valyrian Freehold based off the country of Valyria. Once the most powerful empire in the world thanks to their mastery of magic and dragons, something happened one day that literally destroyed the country, known offhandedly as the Doom of Valyria. Now sailors and explorers fear to even come close to the country's waters as they are storm-wrecked, choking with dangers and the land itself is an inhospitable waste reduced by volcanic eruptions, leading to the proverb that the Doom still rules Valyria.
There is such a zone in the Blake's 7 episode "Pressure Point", surrounding what the Liberator crew thought was Control. It wasn't. The crew get through it via wire cutters and running fast.
LOST has the Dark Territory, which seems to be where the Temple is and where the smoke monster hangs out.
Danielle: Dynamite, by the Black Rock, in the Dark Territory.
Hurley: Well, that's three reasons to go right there.
In Star Trek, even landing on Talos IV was the only death sentence left on the books. It kinda made sense due to the mind-controlling aliens.
Farscape has "Tormented Space" which most species stay away from due to dangerous electrostatic anomalies and the barbarism of the natives. Of course, the heroes have to go there to escape the various bad guys.
On Stargate SG-1, Teal'c tells Daniel of a world whose address is know to all Jaffa and Go'auld as a place to be avoided at all costs. SG-1 sets out for the place at once. The planet is under Asgard protection and has a device that teleports any Jaffa or Go'auld to a maze that the symbiote cannot escape from.
In Firefly, you'd have to be insane to even consider going into Reaver-occupied space. The Movie, of course, sees our protagonists forced to do just that.
A later issue of the National Lampoon had a bizarre story of a reporter's unravelling the account of hayseed comic Junior Samples' attempt to join Frank Sinatra's "Rat Pack". A lead sends him to the defunct "Hee Haw Land" amusement park, which is divided into three zones - Hee Sector, Haw Sector, and the Forbidden Zone.
In the backstory of Mad Daedalus, King Minos erects a shrine to the "goddess" Ariadne Shrine, then forbade his subjects from visiting, lest they discover that she is really an AI from a crashed alien spaceship.
Warhammer 40,000 has the Eye Of Terror, a Negative Space Wedgie caused by a large chunk of the galaxy permanently overlapping with the setting's equivalent of hell. Not recommended as a holiday destination.
The area of space between the Tau Empire and the Farsight Enclaves is actually known to the Tau as the Forbidden Zone. Ever since commander Farsight broke off from the Tau Empire, travel to the area has been forbidden by the Ethereals, while the Enlaves have fortified their side with automated defence stations that shoot down non-friendly ships and probes.
Nobilis gives us the Dead Zone of Libya, a region which has had all hope, life, and meaning scoured from it by the Excrucian Textrix the Deacon. While you can break a man by leaving him there for a day or two, no dictatorship takes advantage of this, because the trait that makes things memorable is a trait the Dead Zone doesn't have any more.
Tormenta, a Brazilian RPG setting, has its namesake, the "Torment Areas". Easily recognizable by being covered in blood-red clouds at all times, these are regions that were taken over by a very Lovecraftian interdimensional species, making the places absurdly dangerous to anything that finds itself inside.
The flash game 'The Day': No one leaves the plantation, ever. Other characters keep warning to "Not go in the trees, or the guards will kill you". Naturally, the player is able to ignore the intended gameplay and leave the plantation if they want, and get an alternate ending: after a winding, fenced off area you enter an abandoned building and find the shriveled carcass of your uncle, whom attempted escape many years ago. When you leave out the front of this building, the camera pans out to reveal all of the land besides the plantation is a cratered wasteland.
Misty Island in Jak and Daxter, which is where the entire plot for the game is introduced. The Wasteland and anywhere located outside the walls of Haven City also qualify in Jak 3 and Jak II, respicatively.
Many, many dungeons and locations in RPGs and other video games.
The game S.T.A.L.K.E.R. takes place entirely in a fictional version of the forbidden zone that surrounds the Chernobyl nuclear power plant.
Sectors X, Y, and Z in Star Fox 64. Although many battles take place at these locations, the game's background information reveals that, prior to the war, civilian craft were restricted from going to them, due to the prevalence of pirates and strange radiation that interfered with spaceship functionality.
In Half-Life 2, Gordon Freeman arrives at Black Mesa East and is taken on a quick tour, including a boarded-up mine shaft that leads to the city of Ravenholm. "We don't go there anymore," Alyx says. Unsurprisingly, the only other path is soon blocked.
Geneforge: Two hundred years ago, something went horribly wrong on Sucia Island. Access is punishable by death. Naturally, you're stranded there, and naturally, you're about to find out why it was abandoned.
Thief: The Dark Project: The Sealed Section of the Old Quarter. The information Garrett has on it is sketchy (he knows that there was some sort of disaster involving zombies and raging fires 50 years prior to his time, but he doesn't know precisely what happened or why). Having been hired to retrieve an artifact from the quarter's cathedral, he's about to find out.
In Immortal Defense the player character actually ends up becoming the cause of a forbidden zone because of his tendency to destroy any ship that approaches his old home.
Sewer Shark's Sector 19. Your boss, Stenchler, explicitly has it off-limits to sewer jockeys, and your copilot Ghost gets irked when Falco shows off video she shot in the tube sections nearby. In a variation on this trope, Sector 19 is only off-limits to keep all the jockeys from making their way to Solar City, since Stenchler is really the villain.
In the Fallout: New Vegas expansion pack Old World Blues, Dr. Mobius harasses and threatens the Think Tank from his dome-shaped area in the Forbidden Zone. It used to be the X-42 robo-warfare facility, from which Mobius creates and unleashes his deadly, intellect-draining robo-scorpions.
The whole of the Big Empty may count, as do the Sierra Madre Villa and The Divide.
Grand Theft Auto: San Andreas has Area 69, a military and research compound that instantly gives you a 5 star warrant level if you approach it and you'll be shot down by missiles or the military's fighter jets if you approach the area by air. There's one mission where you do get the chance to sneak into the facility and see why the area is so heavily guarded; using alien technology, the military created a jet pack that allows the wearer to fly. You get to keep it as well once you complete the mission.
Shadow of the Colossus occurs entirely inside one of these. In fact, it's so forbidden that the player is the only one around for most of the game, if you don't count the small woodland animals and the horse.
The Secret of Monkey Island 2: Le Chuck's Revenge plays with this. When on your ship, try to go anywhere that isn't a plot-relevant location and your helmsman will inform you, "We can't go there, mon. That is the Forbidden Triangle." Or Hexagon, or Dodecagon, or Reuleaux Triangle, or Lemniscate...
Inverted in the first Sluggy Freelance parody of Harry Potter, where one of the characters says he's referred to as "Homnigrits, the man who goes where few fear to tread". (The mall, mostly. Not many people fear to go there.)
In Beyond the Canopy, the Forest's Navel is a place where nearly all are terrified to go (even the resident Nightmare Fetishist), believing that it's cursed or just a deadly, impassible labyrinth of thorns. The one person who does go there regularly is widely believed to be cursed himself.
The Serpent's Pass is a quick route to Ba Sing Se, the only land passage across the large inland sea that separates the sections of the Earth Kingdom, and for those without tickets or passports for the hidden ferry it is the only way to reach the safety of Ba Sing Se. Of course, considering the entrance signpost actually says "Abandon Hope," and only the most desperate of travelers dare to take this deadly route, maybe you should think twice before crossing this isthmus. Hint: there's a giant mother-flipping serpent swimming around.
The destroyed Fire Nation warship near the Southern Water Tribe village in the first episode straddles the line between Forbidden Zone and Call Receival Area. It was probably forbidden because it had been rent through with ice and was unstable, not because the elders knew of any boobytraps, but the flare Aang and Katara set off summons Zuko to provide a reason to get out of dodge.
The cartoon Sonic Sat AM had a Forbidden Zone where a once-evil wizard lived.
The short-lived Ruby-Spears animated series known as Piggsburg Pigs featured an area right outside of their city that was literally known as the Forbidden Zone, and for good reason....it was populated by all manner of demonic creatures, from swamp monsters, to vampires, to aliens. Though for some reason, these creatures were more humanoid in appearance, whereas the Piggsburg populous were all anthropormorphic pigs that wore clothes. So whichever one was truly more frightening is left up to you.
Obviously Futurama (as seen in the page quote). Also in the episode "A Bicyclops built for two", there was the Forbidden Valley. As it turns out however, the Forbidden Valley actually seperates and stops Alcazar's brides from seeing the other four identical castles, where the other brides live.
In one of the flash forward episodes of The Simpsons, a teenage Bart works as a delivery boy for Apu, who tells him he has to deliver groceries to an elderly shut in (Mr Burns) in the "Forbidden Zone". Not the one with the smallpox, or radioactivity, or eternal midnight, but the one with the Uniclams.
Basically anything that isn't The Great Valley in The Land Before Time series, following the original (since that was spent getting to The Great Valley).
Null Void in Ben 10. Kevin was scared and horrified of going there (or threatening to go there), Ben claimed it's worse than prison, Argit hesitating to go there and even Vilgax had an eye twitch by just mentioning it, calling it accursed.
In The Lion King, it is strictly forbidden for Simba and Nala to visit the Elephant Graveyard, as that is where the hyenas live.
The Dreamstone has an area of Viltheed called "the Dark Side", an area of the Sleeping World that is unexplored and rampant with deadly creatures. Curiously concept art for the show also lists a similar area titled this trope (likely what the Dark Side evolved into for the finalized show).
For a time in the 1980s the Libyan government declared the Gulf of Sidra off-limits to international shipping, calling their boundary the "Line of Death." Yet oddly, a pair of U.S. aircraft carrier battlegroups encountered no trouble at all when they entered it. The Libyans did send aircraft after them on two occasions, in each case the Libyans were blown out of the sky by F-14s.
Centralia, Pennsylvania. An underground coal fire expected to rage for thousands of years means it's strictly off-limits. This town served as inspiration for Nothing But Trouble and Silent Hill. To this day, there are still people who refuse to leave, although their numbers are dwindling.
Gorge of Despair, in Kings Canyon.
Death Valley, California has the distinction of being the hottest place in the Western hemisphere.
The Exclusion Zone around Chernobyl in the Ukraine, including parts of Belarus. These days, you can actually go there, but not for long. Note that hundreds of people work there daily, and their numbers are likely to increase as the new radiation shield needs to be built around the reactor soon. Still, the area is large enough that a casual visitor is unlikely to see anybody else during a brief visit.
The southern half of Montserrat, a British territory in the Lesser Antilles, has been an Exclusion Zone ever since volcanic activity rendered the region uninhabitable in the mid-90s.
During World War I, the space between the enemy trenches on the front lines was called the No Man's Land. It was aptly named. Anyone foolhardy enough to step foot on it would probably be shot by the enemy, up to thousands of times per second, if they didn't step foot on the landmines scattered between and around the barbed wire.
Area 51. In hindsight it was probably a bad idea to burn radioactive waste in their backyard without any safety measures.
The DMZ betwixt the Koreas.
This is what the area around the Yucca nuclear waste repository may look like to future humans, depending on the exact method that the government employs to discourage passersby from wandering inside to see what's there. One proposed method is to build a large field of concrete thorns around it.
No Fly Zones, where aircraft are forbidden to fly on pain of being shot down. This is a common response to regional instability, to prevent combatants with aircraft from launching bombing strikes against civilians.