This prison doesn't need walls, or guards, or security cameras. No one's stopping prisoners from escaping. The jailor might even point them in the direction of the convenient escape route. The door's right there! It's not even locked! Why doesn't everyone just leave?
Well, because escape would be suicide. The secure facility remains secure because it is located in an extremely inhospitable environment. It might be in the middle of a vast desert or tundra, such that anyone foolish enough to leave would die of exposure. Alternatively, the surroundings could be populated by Super-Persistent Predators or other deadly creatures. In extreme cases, the prison may be smack in the middle of the ocean, or at the top of a mountain with a hundred-foot drop on all sides. In sci-fi settings it could be in a space ship or station, on an asteroid, or a Death World. Needless to say, it's safer just to stay inside.
Often serves as an example of Morton's Fork. May be how a villain carries out Released to Elsewhere. If there's any chance at all of success, the escape route is likely to be a Death Course; sufficiently badass prisoners may theoretically win their freedom. Being imprisoned in such a facility, however, may lead to the realization that Hope Is Scary. Some prisoners may choose to commit suicide using the escape route, preferring death to imprisonment.
Often overlaps with Penal Colony, which are built in remote (but not necessarily deadly) locations by definition.
- Impel Down in One Piece is situated in the bottom of an ocean - which, for Devil Fruit users, is no good news. Not just any ocean either; it's in the Calm Belt, a zone on the Grand Line's border where there are no winds blowing and Sea Monsters are abundant; only Seastone-coated ships (usually that of the Marines) can pass through it easily.
- The World of Toriko has no shortage of insanely deadly environments, but the people who build the three Great Gourmet Prisons still decided to go the extra mile. The Sky Prison floats ten kilometers above the ground. The area around it is prone to tornadoes and inhabited by giant carnivorous birds with a taste for human flesh. The Prison Submarine is submerged two kilometers below sea level and the waters around it are filled with carnivorous fish, just in case someone manages to survive the water pressure at that depth. The Honey Prison hangs on the edge of a cliff above one of the harshest environments in the human world - areas with abnormal climates. In the summer frequent eruptions flood the entire zone with magma and temperatures rise to the point when even the air can burn human skin upon contact. In the autumn the area is covered by a fog so thick that vision is limited to just one meter and so poisonous that inhaling it three times is enough to stop a human heart. In the winter temperatures can drop to 200 below zero. Only the spring period is survivable... which is why all horrifying monsters, who live in that area, come out of hibernation and become active during that season. The only safe road ("safe" meaning, that monsters are less likely to attack there) is blocked by several kilometer-long drawbridges and specifically trained monsters.
- One episode of Outlaw Star had Gene infiltrating a prison that was located on a high-gravity planet. No prisoner sentenced to go there had lived to see the end of their stay because their hearts gave out from the gravity's strain sooner or later.
- In Serenity: Leaves on the Wind, Zoe is sent to an Alliance Penal Colony on a planet where the terraforming didn't take, leaving it a barren desert. The prison camp doesn't have walls—if you leave any way but by ship, you die of thirst—and the guards don't bother breaking up fights between the inmates or bother to chase you if you run. Zoe excepted: the guards quickly pursue her once they realize she's running to meet Mal and the others, who came in on Serenity.
- Parodied in the very first Judge Dredd story, which ends with the perp being sentenced to a prison called Devil's Island — which is a road island surrounded on all sides by a multiple-lane super-freeway with traffic streaming along it at high speeds at all hours.
- One issue of Superman has The Villain contain a pair of hostages within a magnetic force field generated by one of his devices. The field generator and the hostages are hidden within an active volcano, where the extreme heat would boil away the hostages in seconds without the protection that the force field offers. Superman's dilemma is how to extract the hostages and also keep their compartment intact.
- The underground Klingon labor camp Rura Penthe where Kirk and McCoy are imprisoned in Star Trek VI: The Undiscovered Country has nothing preventing prisoners from escaping—except the extreme cold and storms of the surface, where death by exposure would be a certainty (technically, there's also a magnetic field to prevent transporter use). In fact, prisoners are threatened with expulsion to the surface if they don't work.
- The Dark Knight Rises: Bane's prison has no guards or fences, just a gaping hole for a roof that only one child has ever managed to climb out of. Many more have fallen to their deaths trying to escape.
- The Bridge on the River Kwai is set at a P.O.W. Camp deep into the Burmese jungle. The camp has no fence to prevent escape because, as the Japanese commander puts it: "If the wardens don't kill you, the jungle will." Of course, he is proven wrong.
- The Chronicles of Riddick: The Crematoria Prison is located on a planet orbiting an extremely bright sun. Temperatures on the surface vary between so hot during the day that you'll be instantly incinerated and so cold during the night that you'll instantly freeze to death. The outside is only survivable for a short period during twilight.
- Outland: The high-security cells on the station's Sheriff's office have no gravity and no oxygen—the prisoners are encased inside of a spacesuit connected to an oxygen umbilical cord and left to float around until their sentences are up or they confess. This comes to bite O'Neill in the ass when one of the prisoners (which has information he needs to uncover the conspiracy within the station) is "left alone" by the other (corrupt) deputies and this allows an assassin to cut the umbilical, killing the prisoner with Explosive Decompression.
- Wild Wild West: After Loveless captures Jim and Gordon, he places them in a small unguarded entrapment in the middle of nowhere. They can leave whenever they want, but doing so will activate a device that sends a Deadly Disc after their magnetic collars. Jim being Jim, he triggers it without even thinking.
- In Papillon (1973), when the titular character is sent to Devil's Island, he's told that conditions are quite lax there as the sharks make sure no-one escapes.
- Alien³. Incarceration on the penal planet of Fury 161 is entirely voluntary. There's a minimal staff with no weapons, as there's no place for anyone to escape to without a functioning spacecraft.
- In A Game of Thrones, the Arryns' cells have only three walls... with a 600-foot drop off the side of a mountain on the fourth side. The Lord of the Eyrie also tries to force the imprisoned Tyrion to leave their castle via the Moon Door (again, with a 600-foot drop on the other side.) When Tyrion manages to get pardoned, Lady Lysa Arryn manages to do Death By Freedom again (he can now leave the castle via the road full of shadowcats and hostile tribes.)
- In Going Postal, when Vetinari is meeting his new Boxed Crook Moist von Lipwig, he tells Moist that if he doesn't like the offer he can simply walk out that door. When Moist goes to check, the door leads to a deep pit, possibly full of spikes; it's so deep Moist can't even seen the bottom.
- In the sequel Making Money, when placed in the same scene and offered the same choice, Moist theatrically goes to test the depth of the "alternative"... only to find that now it's an ordinary exit door, because this time Vetinari really is giving him the option to refuse.
- Holes. The juvenile detention camp "Camp Green Lake" has no guard towers or fences, and most of the counselors aren't even armed (and Mr. Sir, who is, says that he will not waste a bullet on an escaping prisoner)... but the camp is in the middle of the desert, and has the only water for 100 miles, and the only fauna is highly poisonous spotted lizards. Anyone who wants to leave can leave, only to die of thirst or be forced to come back.
- In The Stars My Destination, everyone can teleport, so criminals are kept in a location they don't know. You are welcome to Tele-Frag yourself whenever you want.
- Tribesmen of Gor. The salt mines of Klima are staffed entirely by male slaves. There are no guards, and you're free to leave at any time. But it's surrounded by hundreds of square miles of desert, and canteens are limited to small sizes; you'd die of thirst & exposure if you try to leave.
- Honor Harrington:
- The native life of Haven's secret Penal Colony of Hades is indigestible to humans, the prisoners were scattered in camps all across the planet with the only source of food being periodic supply shuttles.
- From Torch of Freedom: after the Battle of Torch, a POW camp is set up on one of Torch's islands. There's no guards on the island itself, and only a few patrol boats in the ocean around it ... but the local sea life will eat just about anything short of rocks, and the surviving StateSec prisoners learn quickly not to try swimming/boating to the mainland.
- At the end of the Icerigger Trilogy, some human lawbreakers need to be confined at the Tran-ky-ky outpost of Brass Monkey. The settlement isn't nearly big enough to have a suitable prison, so the criminals are herded into a vacant warehouse and stripped of all but the minimum of clothing. This is more than enough to keep them confined, as ambient temperatures at Brass Monkey hover around -30 degrees Celsius at high noon, with a non-stop lethal wind chill.
- In Jack Vance's Throy, the Big Bads of the entire Cadwal Chronicles series end up marooned in one of these, one that they devised for imprisoning their own enemies. Just a small stockade with no guards at the top of an extinct volcano, smack in the middle of a Death World continent where everything is a predator.
- In The Walking Dead, Rick chooses to allow one of the prisoners to escape into the walker-infested woods rather than wasting a bullet on him.
- Star Trek: Voyager: One episode has Kim and Paris being sent to an alien prison. The only access to it is a chute from which new prisoners and supplies are delivered. After some effort, Kim manages to climb the chute, only to find that the prison is actually free-floating in deep space. After that, all they can do is survive until Voyager finally manages to locate them.
- Stargate SG-1 had an underground prison colony accessible only through a Circle Gate or a Stargate with no Dial Out Device, which is used to deliver food rations for the prisoners. The prisoners believe that it's possible to escape through the Stargate during the moment it opens, which is impossible, as anything in front of the gate is vaporized when the energy burst starts. The team manages to escape by using cold fusion, invented by a scientist named Linea (unbeknownst to them, she's a mass murderer), and manually spinning the inner circle and locking each coordinate.
- The Elder Scrolls
- In Morrowind, the Ministry of Truth is a hollowed out moonlet suspended in the air above Vivec city. In the distant past, it was hurled at the city by Sheogorath, the Daedric Prince of Madness, and frozen in place by the Tribunal deity Vivec. It was hollowed out for the Tribunal Temple to use to imprison Dissident Priests and other religious criminals (the interpretation of this is deliberately vague). Simply reaching the Ministry requires Levitation, and since prisoners have their Magicka magically drained and aren't allowed to keep scrolls/potions, this makes escape nearly impossible. You thankfully never have to break out of it, but you do have to break in in order to free an ally during the main quest.
- In Oblivion's Shivering Isles expansion, the prisons do confiscate your stuff, but your cell is not locked and you are free to leave. Doing so does involve trying to brave the dungeon creatures with your bare hands and spells, however...
- Skyrim. The Chill, the prison in the Winterhold, runs on this. They do not confiscate your swag, and they do not guard your cage, but it is located in an icy cave on a small island in the middle of a frozen ocean. If you beat the Frost Atronachs on the island and swim through the frigid ocean to freedom, no one is going to object.
- The Prison Ship Purgatory in Mass Effect 2 is one as it is located in what is the least-survivable environment known to life itself: The cold vacuum of space. The warden who runs this tight ship, a corrupt Turian who is as likely to extort your planet for money, lest he "misplace" a particularly dangerous prisoner or two on it as he is to look at you, boasts that he is able to prevent escape attempts simply because there is no where for the prisoners to go, and if they act up, he'll vent the cell of the trouble-making prisoner into space anyways. Unfortunately, he makes the mistake of trying to enslave Commander Shepard for ransom money, and Shepard responds by shooting their way through the ship and waking up the resident Tyke Bomb and it only goes downhill from there.
- The prison camp in Final Fantasy VII is in the middle of a desert. You get there by being dumped down a chute from the Golden Saucer, and nobody bothers to guard the place because the desert is impassable. The other prisoners will all tell you that people who go into the desert don't come back. (However, to prevent the game from becoming unwinnable, if you wander out into the desert, first you get lost but after a while someone shows up with a chocobo stagecoach and takes you back to prison.)
- In Jedi Academy, Jaden is put into one of these prisons when he is captured by the Empire. The doors of his cell are open, but the prison complex is swarming with stormtroopers and their commander is fond of Hunting the Most Dangerous Game. Oh, and they took Jaden's lightsaber.
- There are multiple indications throughout the Portal series that the world outside the Aperture Science complex poses more danger to Chell than the tests endlessly invented by the murderous AI GLaDOS inside.
- Avatar: The Last Airbender:
- The Boiling Rock is a Fire Nation prison for some of their most high-value captives located in a volcanic crater filled with a boiling lake, which gives it its name. Anyone attempting to escape is boiled to death.
- The Fire Nation's prison rig is located hundreds of miles out to sea. While that may not sound that dangerous, it's still pretty much a death sentence for anyone trying to escape.
- Superman: The Animated Series: When the Government Conspiracy that created Volcana manages to capture her again, she is placed inside of a special cell that has absolutely no oxygen (and thus nothing for Volcana's powers to burn) and the only supply comes from a mask and umbilical which is controlled by her captors. She is free to try to get out, if she can do it before she suffocates to death.
- A reason why Australia was chosen to be the primary Penal Colony of the British Empire is that it was a big island far from the mainland where Everything Is Trying to Kill You.
- The Vichy French regime in Algeria ( a puppet government taking its orders from Mussolini and Hitler) interned British and Commonwealth military personnel who fell into its hands in a concentration camp in the South Sahara. Security in this notorious camp was light because there were two hundred miles of desert on all sides and the local Arabs were paid to bring back corpses, rather than living escapees.
- Some of the camps of The Gulag in the Stalin-era Soviet Union had very little in the way of perimeter security. Since these particular camps were located in some of the remotest areas of Siberia, there was simply no place for escaping prisoners to go, even if they did leave. Sometimes such camps were initially established by more-or-less dumping the first load of prisoners in the wilderness with a few supplies; they could either build their own crude "prison", or die.