In video games with wide open worlds built on [[{{Backtracking}} revisiting the same locations over and over]], there are certain places that you can only enter once and never again. Sometimes this is because the place no longer exists thanks to being a DoomedHometown or a CollapsingLair. Sometimes it's because the plot keeps you out of it. Whatever the reason, these are places that can never be returned to.

The items inside the dungeon are frequently LostForever and there are often times that you can only fill up your MonsterCompendium by grinding there.

'''Note:''' In order to qualify a game must be generally be open to {{backtracking}} and not just have a linear advancement through it.
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!Examples:

[[foldercontrol]]

[[folder:Action Game]]
* In the first Xbox ''VideoGame/NinjaGaiden'', you can't go back to the Ninja fortress of chapter 1 nor in chapter 3's airship since it crashes.
* In addition to the obligatory CollapsingLair at the end of each game, the ''Franchise/ResidentEvil'' franchise has a number of destroyable locations that occur mid-game, such as the Hospital in ''VideoGame/ResidentEvil3Nemesis'', the part of Rockfort Island in ''VideoGame/ResidentEvilCodeVeronica'' where Claire starts out (destroyed shortly before her escape), and the train in ''VideoGame/ResidentEvil0''. The only exception thus far is the very first game and its remake, where the entire mansion and its outlying grounds are fully available to explore right up until you confront the final boss.[[note]]If we want to be picky, there is one room that is permanently closed off to Jill if you don't disarm the ceiling trap first.[[/note]]
[[/folder]]

[[folder:Action Adventure]]
* ''VideoGame/TheLegendOfZeldaPhantomHourglass'' has the fourth dungeon, the Ghost Ship. It has a TheDevTeamThinksOfEverything moment: if you leave without taking its Heart Container, the only item in the dungeon relevant to OneHundredPercentCompletion, it is sent to you via mail to avert it being LostForever.
** ''VideoGame/TheLegendOfZeldaSkywardSword'' has the final dungeon, the Sky Keep, which disappears once you [[spoiler: grab all of the Triforce Pieces.]] It has no Heart Pieces.
** ''VideoGame/ZeldaIITheAdventureOfLink'' provides an example with the Palaces that become Mountain squares on the overworld map after you beat them, but only after you both defeat the boss and collect the required item, fortunately. The only things that can truly be LostForever are some ExperiencePoint bonuses.
* In ''VideoGame/CaveStory'', Waterway is accessible only from an area whose entrance shuts permanently after a certain point. Depending on which story-path you take, ''the entire Labyrinth'' may become inaccessible.
* The insides of Demon Whale in ''VideoGame/{{Alundra 2}}'', which becomes unavailable after the thing turns back into a normal whale.
* ''VideoGame/{{Okami}}'' has the Moon Cave dungeon that cannot be accessed again once your defeat Orochi and leave it. There is also Oni Island, the miniature sections of the Imperial Palace, the Sea Dragon's body and [[spoiler: Past Kamiki]]. This is generally not frustrating since these areas only contain VendorTrash, but no important secret item -- with one exception to the spoilered area, which has a dog to feed. If you overlook this on your one visit to that area, you cannot get 100% Animal Tome completion.
* ''VideoGame/{{Okamiden}}'', the sequel to ''Okami'', is not so forgiving. It has the Five-Story Pagoda, the Moon Cave (again), the Underground Ruins, and the Ice Cavern, all of these contain unique items that are needed for HundredPercentCompletion.
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[[folder:Eastern RPG]]
* ''VideoGame/{{Kingdom Hearts}}'' has Oogie's Manor in [[TheNightmareBeforeChristmas Halloween Town]]. [[spoiler: After defeating Oogie Boogie, he [[OneWingedAngel merges with his manor]] for another fight.]] Thus the manor is destroyed afterwards, as well as all its treasure--including a Red Trinity Mark that, if missed, [[LostForever can't be recorded in the journal]]. The UpdatedRerelease moved that Trinity Mark to fix the issue.
* The ''Franchise/FinalFantasy'' series has plenty of these.
** ''VideoGame/FinalFantasyII'' has Emperor Palamecia's cyclone castle, which dissipates once he's defeated. Unfortunately, the cyclone also wiped half the towns off the world map before that, so here it's not just dungeons that get the worst of this trope. The towns are still visible on the map, but they are completely wrecked and cannot be entered.
** ''VideoGame/FinalFantasyIII'' has a floating Hyne Castle, which after finishing gets planted into a forest you're not allowed to get back to.
** ''VideoGame/FinalFantasyIV'' has the Tower of Zot, which [[CollapsingLair collapses once finished with]], as well as the Giant of Bab-il, and the Tower of Bab-il's two parts. Unlike the first two, the Tower of Bab-il actually remains on the world map--it's simply closed off.
** In ''VideoGame/FinalFantasyVI'' there's the Imperial Camp, Phantom Train, Magitek Research Facility, Sealed Cave, Floating Continent, and Cyan's Soul.
*** And Kefka's tower, but only half of it.
** ''VideoGame/FinalFantasyVII'' has several locations that can only be visited once to name of. Sectors 1 and 5 reactors, Shinra Headquarters (won't be revisited again until the raid late in disc 2, and can't be revisited after that), Cave of the Gi, Corel Prison, Temple of the Ancients, Gaea's Cliff (and by extension the Whirlwind Maze), Underwater Reactor, and Midgar sector 8 during the raid.
** In ''VideoGame/FinalFantasyVIII'', there's Dollet Communications Tower, Galbadia D-District Prison, Missile Base, Galbadia Garden (during the attack), Great Salt Lake and Lunatic Pandora (only visited twice) leading to almost all locations inaccessible due to Time Compression. Not to mention the Laguna dream sequences.
** ''VideoGame/FinalFantasyIX'': Evil Forest, the Ice Cavern, Cleyra, Fossil Roo, and all of Terra (including Pandaemonium).
** ''VideoGame/FinalFantasyX'' has Home [[spoiler:which is destroyed immediately after leaving]], the Bevelle temple and the Via Purifico (which are blocked off).
** ''VideoGame/FinalFantasyXII'' has several, and in an uncharacteristic act of kindness, the programmers indirectly tell you which ones by giving you a prompt about not being able to leave them until you finish them when you try to save in them:
*** Nalbina fortress which is only there in the prelude due to it being destroyed.
*** Rabanastre Palace during the heist.
*** Nalbina Dungeons which is only accessible during your escape.
*** Several airship dungeons including the Leviathan and Shiva.
*** Draklor Laboratory in Archades.
** Due to the linear nature of ''VideoGame/FinalFantasyXIII's'' first ten out of thirteen chapters, every single area visited then is one time only.
* In both ''VideoGame/MOTHER1'' and ''VideoGame/EarthBound'', [[WackyLand Magicant]] vanishes. In the first game, Magicant can be revisited prior to completing a particular subquest; in the latter, it's a true One Time Dungeon with a few special items that can be LostForever.
* ''VideoGame/MOTHER3'' uses a Chapter system, but most dungeons and areas in the game can be revisited in at least one later chapter (although the enemy types and layout will change with the plot). The major exceptions are the Attic Dungeon in Chapter 4, which becomes inaccessible once the Chapter ends with its completion, and the Thunder Tower, which is only accessible in Chapter 5 because the story at that point involves infiltrating and destroying it.
* The Distortion World in ''[[VideoGame/PokemonDiamondAndPearl Pokémon Platinum]]''. The initial, plot-relevant area is one-time, anyway; you ''can'' enter it again later, though it's a different section of it.
* N's castle in ''VideoGame/PokemonBlackAndWhite'' is destroyed and can not be revisited. It can in the [[VideoGame/PokemonBlack2AndWhite2 sequel]], though.
* The dungeons you explore in the future and The Nightmare in ''VideoGame/PokemonMysteryDungeonExplorers''
* Subverted to a degree in ''VideoGame/PokemonMysteryDungeonGatesToInfinity''. While the Glacier Palace and the Magnagate dungeons used to reach it can't be visited again through normal methods, it's possible to temporarily be warped into them for a few floors while exploring specific dungeons in the post-game.
* The S.S. Anne in ''VideoGame/PokemonRedAndBlue''.
* In ''VideoGame/ChronoTrigger'':
** The Black Tyrano fortress in 65,000,000 B.C. is destroyed when Lavos crashes into it. Mt. Woe in 12,000 B.C. is no longer accessible after the chain breaks and it falls into the sea. The Ocean Palace in 12,000 B.C. is no longer accessible after [[spoiler:Lavos awakens, destroying it and the Kingdom of Zeal]].
** [[spoiler:The Black Omen]] is also a possibility, depending on [[spoiler: which time period you finish it in. Completing it in the earliest time period (12,000 B.C.) prevents you from finishing it in the other two (600 A.D. and 1,000 A.D.) Going from the most recent time period to the oldest allows you to complete it 3 times total.]]
* In ''VideoGame/BreathOfFireI'', Nanai and the dungeon beneath it are destroyed after you leave. Neither Mogu nor Mote's dream dungeons can be re-entered once you complete them. The Goddess' Tower is also destroyed [[spoiler:after Jade releases the Goddess]].
* ''[[VideoGame/MarioAndLuigiSuperstarSaga Mario & Luigi: Superstar Saga]]'' has the ''entire beginning of the game''; specifically, Mario's house, Peach's castle (where you fight Bowser), Toadtown Square, the Koopa Crusier, and the small bit in Stardust Fields before the Border Jump minigame.
** ''MarioAndLuigiPartnersInTime has the Shroob mothership, visited once after Thwomp Volcano and inaccessible as a dungeon afterwards.
* ''All story dungeons'' in ''VideoGame/HyperdimensionNeptunia''.
* Twice in ''VideoGame/{{Xenoblade}}''. First, a good chunk of the Ether Mines in Colony 6 becomes unavailable after the boss has been defeated; and well after that, it ups the ante by locking away [[spoiler:the entire freaking Mechonis, i.e. the other half of the game world, after it's been destroyed]].
* [[ShipLevel The beginner dungeon]] in ''VideoGame/{{Dubloon}}'' cannot be accessed after [[HopelessBossFight Bradley curb-stomps you]]. Thankfully there is nothing in this dungeon that can't be acquired anywhere else.
* In ''VideoGame/{{Ys}} IV''(both versions), the raising of the Ancient City causes certain dungeons to be destroyed or rendered inaccessable. After the city of Kefin reappears in ''V'', the desert town is buried by a sandstorm, and the dungeon under Xandria collapses [[CollapsingLair while you're escaping from it]]. In ''VI'', the Romun Fleet is destroyed by Galba-Roa after you're finished there, and Zemeth Sanctum also is destroyed by the Ark's revival.
* The ''VideoGame/GoldenSun'' franchise has a few:
** In the first game, the very first dungeon, Sol Sanctum, becomes inaccessible after you've completed it.
** ''[[VideoGame/GoldenSunDarkDawn Dark Dawn]]'' has multiple [[PointOfNoReturn Points of No Return]], but two stand out for completely opposite reasons. The first one is the Clouds of Passaj, which come immediately after the second PointOfNoReturn and the only one where the game warns you ahead of time that there's no going back after this point. [[note]]Ironically, every area in between the first and second PointOfNoReturn actually ''does'' become accessible again after the final PointOfNoReturn and there's one sidequest that can only be completed by returning during this time, though it still counts as a Point of No Return because there's one Djinni that can only be obtained before this point.[[/note]] After getting through the Clouds, you can't reenter them. The game's fairly merciful, though, in that the only treasure chests in the area contain common items that can easily be bought in item shops. The second, far more insidious one is the Belinsk Ruins. There's nothing to indicate that once you have the band play Arangoa Prelude, you won't be allowed to leave Belinsk until you complete the Ruins and even less to indicate that once you do, you'll have to leave Belinsk by sea when you entered it by land, and furthermore that Arangoa Prelude was in fact the third [=PoNR=] and that leaving Belinsk after [[spoiler:the Grave Eclipse has started]] is the ''fifth'', since you also can't go back into the Ruins after you've beaten their boss. There are ''two'' special summons that are only available during this time, as well as one Djinni and some fairly nice items in the dungeon's chests.
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[[folder:Interactive Fiction]]
* ''VideoGame/{{Eamon}}'': the Beginner's Cave (on the game's Main Hall disk) is accessible only once. The game checks when the player tries to access it; only a true beginning character is allowed to enter, and a player who finishes the cave is no longer a beginner.
[[/folder]]

[[folder:MMORPG]]
* Pre-Searing Ascalon in ''GuildWars'' invokes this via DoomedHometown. Leveling all the way to 20 here is the only way to get the Defender of Ascalon title.
* In ''VideoGame/MapleStory'' once you leave Maple Island, you can't go back. That ship inexplicably only goes in one direction. The game blends this with GuideDangIt and LostForever, because there is a special quest reward that will boost your HP recovery while resting that you can only get by sticking around.
* ''[[VideoGame/WorldOfWarcraft World of Warcraft: Cataclysm]]'' introduces several in the form of {{Doomed Hometown}}s for the Worgen and Goblin races. It is possible to return to Gilneas, although there is no longer anything there (and that means absolutely ''nothing'', no [=NPCs=] and no enemies, which arguably makes an already BleakLevel even [[NothingIsScarier creepier]]). However, Kazan and the Lost Isles are completely sealed off once you leave.
* ''VideoGame/CityOfHeroes'' is generally very good when it comes to backtracking, as you can replay most story arcs and badge missions at will via the Flashback System. However, Praetorian Characters get hit by this trope ''hard''. The first three Praetorian zones can be revisited at any time, but the story arcs can ''never'' be replayed once you outlevel them. The Praetorian Alignment Badges and Temporary powers are LostForever if you don't have them when you leave. This is due to an issue with the game's KarmaMeter.[[note]]Resistance and Loyalist characters are their own alignments, and certain contacts are only accessible if you have the corresponding alignment. As you can change your alignment multiple times throughout the storyline, being able to replay the arcs as a Hero or Villain would screw things up.[[/note]] Praetoria used to be a much more extreme example of a One Time Dungeon. When the zones were first released, leaving Praetoria at level 20 meant leaving it ''permanently''. There was no way back! Things have gotten much more relaxed now.
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[[folder:Platform Game]]
* ''VideoGame/JakAndDaxter''
** In ''VideoGame/JakIIRenegade'' the final level can't be returned to [[PlayableEpilogue after finishing the game]]. This causes 7 Precursor Orbs (the game's hidden collectables) to become LostForever.
** Various locations in ''VideoGame/Jak3Wastelander'', including (but not limited to) the [[LethalLavaLand Great Volcano]], [[UndergroundLevel Catacombs]], [[EternalEngine KG War Factory]], and [[ItsAllUpstairsFromHere Metal Head Tower]].
* The [[NoobCave tutorial levels]] in ''VideoGame/RatchetAndClank'' games generally can't be revisited after completion. However, in some cases ([[spoiler:Veldin from ''VideoGame/RatchetAndClank2002'' and Aranos from ''VideoGame/RatchetAndClankGoingCommando'']]) an [[RemixedLevel altered version]] of the level appears later on, from which point it can be revisited.
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[[folder:Western RPG]]
* ''VideoGame/TheElderScrollsIVOblivion'' has the Painted World area and a dream sequence that can't be returned to. Closing an Oblivion gate destroys that instance, although it's possible (and indeed likely) to find an identical map behind another gate, but completing the main quest line permanently closes all the gates, cutting off access to Oblivion entirely.
** ''VideoGame/TheElderScrollsVSkyrim'' has Skuldafn, which the Dragonborn cannot reach after the first run through it because one needs to be able to fly to reach it, and the friendly dragon who let you ride him there won't do it again. [[GameplayAndStorySegregation You can't even return after you gain the ability to tame and ride dragons]] from the ''Dragonborn'' DLC.
** ''Skyrim'' also has [[spoiler:Sovngarde]], which is only accessible through Skuldafn, and, by extension, cannot be returned to.
* In ''VideoGame/KnightsOfTheOldRepublic 2'', Goto's Yacht cannot be revisited, as it is destroyed after you complete it.
* In ''VideoGame/{{Fallout 3}}'', completists would be advised to grab the collectible Energy Weapons bobblehead during the brief Raven Rock sequence, since once the door shuts behind you, [[PointOfNoReturn you're never getting back in there]].
** Same for Vault 101 and the Medicine bobblehead, although you get to revisit one final time in the "Trouble on the Homefront" sidequest.
** The Anchorage Reclamation simulation in the ''Operation Anchorage'' DLC, and the Mobile Base Crawler in ''Broken Steel'' are also only accessible once.
** You can go back to Mothership Zeta after completion, but only parts of it; most of the lower half of the ship, including the two optional areas, is locked after the "Among the Stars" quest, and once you teleport to the Death Ray Hub, the teleporter breaks, locking you out of the Weapons and Experimentation Labs.
* The Dead Money DLC of ''[[VideoGame/FalloutNewVegas Fallout: New Vegas]]'' cannot be visited after it is completed (partly due to the Sierra Madre casino being destroyed via LoadBearingBoss), unlike the Old World Blues, Honest Hearts and Lonesome Road DLC. It's not a problem in the PC version, though, as you can use the noclip console command to find a door that takes you back.
* ''[[VideoGame/{{Diablo}} Diablo II]]'': The Cow Level can only be played once per difficulty level.
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