"My hotel doesn't have a thirteenth floor because of superstition, but come on, man. People on the fourteenth floor, you know what floor you're really on. "I'm in room 1401." No you ain't. If you jump out the window, you will die earlier!"Every building housing a top secret operation seems to have a "beyond top secret floor". There's no obvious button for it in the elevators, you can't reach it by stairs, and of course nobody has ever heard of it. Most realistic is a sub-basement, but it could also be higher than the highest official floor, or even squeezed in between floors — though in the last two cases, it's questionable how they've managed to keep it hidden at all, since anyone looking out a window could get suspicious. Typically either magic or sufficiently advanced technology is involved in keeping such a floor hidden. Finding it is a major plot point. It might have been closed off long ago (since it houses a Dark Secret) or it's still being used by the Beyond Top Secret club. In any case, don't expect to just walk in here, not even if you do have security clearance. While it could technically be any number, thirteen is a fairly common choice.
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Anime & Manga
- In both Read or Die OVA and the sequel R.O.D the TV series, there's a secret bookstore that plays a role in the plot. It's hidden in the basement of a skyscraper, and can only be accessed by hitting the buttons in a specific order – unlocking a card-slot where the 'members only' card-key can be inserted.
- The manga Oldboy concerns a prison where rich folks who want someone out of the way, but not dead, can pay dearly to have it done. It's set in a sub-basement accessible by only pressing two buttons on the elevator at the same time.
- In One Piece, the World Government's great prison Impel Down has multiple underwater floors, with the prisoners assigned to a level based on how dangerous they're considered to be. Level 1, the closest to the surface, is for the least dangerous prisoners, while the most dangerous go to Level 5. When Luffy sneaks into the prison to rescue his older brother, the infamous pirate Ace, naturally he's assumed to be on Level 5. It turns out that Ace was actually being held on Level 6, a secret level where the World Government places even more dangerous prisoners such as Crocodile and Jimbei. There's also Level 5.5, located between Levels 5 and 6, that was created by prisoners who escaped from their cells but had no means to escape from the prison itself.
- In XXX Holic, characters are telling Ghost stories, and Himawari tells one of a hotel that was missing a room; from the outside, you could see the window that belonged to the missing room, but inside, the room was blocked off by a wall. When the owners tore down the wall they indeed found another room, which had the words 'FATHER LET ME OUT!' scrawled all over the walls in blood.
- In Eden No Ori, while Akira and co. were in the pyramid, they encountered a staircase which had a missing floor. It ended up being a double-floor room for huge generators.
- The fifth Kara no Kyoukai movie contains a variation in that it's an entire half of a building that's hidden through the use of an elevator that slowly rotates as it ascends and deposits you on the opposite side of the building than you expected. This is so Araya Souren can carry out a magical experiment with Artificial Humans in one half the building reenacting their last day alive and their original (dead) selves in the other, with their original brains located in the basement powering the whole system.
- Comedian Mitch Hedberg commented that some hotels don't have a thirteenth floor due to superstition and hates to break it to them but the fourteenth floor is the thirteenth floor — it makes no difference.
Comics — Books
- In the pre-Crisis Superman comics, the Daily Planet building supposedly had no 13th floor. In reality, the 13th floor existed and was secretly used by an alien tourist bureau dealing in vacations to Earth.
- In New 52 Batman comics, it turns out the Court of Owls has secret bases between the floors of various buildings in Gotham City, including several owned by the Wayne Foundation.
- In Paperinik New Adventures, the Ducklair building has 150 floors, officially. In reality, there is a 151st.
Films — Live-Action
- The entire premise for the movie The Thirteenth Floor hinged on this.
- In Being John Malkovich, Craig Schwartz works on the 7 1/2 floor of the Mertin-Flemmer Building. It isn't a secret or anything, it's just an architectural oddity created to access the portal into John Malkovich. Without a button, it can only be accessed by using the emergency stop on the elevator halfway between floors 7 and 8 and then using the supplied crowbar to pry the doors open.
- The Matrix Reloaded: "There is a building. Inside this building there is a level where no elevator can go, and no stair can reach. This level is filled with doors. These doors lead to many places. Hidden places. But one door is special. One door leads to the source."
- In Brazil, the protagonist reaches a hidden floor by entering a sequence of buttons that play the recurring title motif.
- Implied in No Country for Old Men when Carson Welles is talking to his employer (note that this doesn't stop Anton Chigurh from finding and killing Welles' employer later on).
Welles: You know, I counted the floors from this building to the street...
Welles: And there's one missing.
Employer: (dryly) We'll look into it.
- When Neal starts to actively seek the mystery girl who has been appearing to him in dreams and on billboards in the movie ''Interstate 60", he's directed to an appointment on the 13th floor of a building. When he gets in the elevator, however, there is no button for the 13th floor. Luckily, there's a new poster from his dream girl on the wall of the elevator. This poster reminds him that 10 + 3 = 13. He pushes the buttons for 10 and 3 simultaneously, and the elevator takes him to the missing floor.
- In Oh, God!, protagonist Jerry Landers first talks to God on the 27th floor of a building that has only 17 floors.
Jerry: How do I get to the 27th floor?
Worker: In this building?
Worker: I'm afraid you'd need a can opener. We only have 17 floors.
- Arnold Schwarzenegger is infiltrating The Mafia in Raw Deal. In one scene he gets into a hotel elevator and tells the operator to take him 'down'. When the operator replies "There is no 'down'", Arnie gives him a big tip and is taken down to an illegal gambling den.
- The corporation running the hotel in 1408 believes that 13 Is Unlucky, so they pretend there's no 13th floor. Hence the thirteenth floor is re-numbered as 14 (just as is the case in many real-world hotels).
- In Nightmare on the 13th Floor the hotel floor has been closed after a maniac murdered several guests many decades ago. On the outside the windows have been hidden with statues and other decorations. It's only accessible by using a special key in the elevator. A cult worshiping said maniac continues to murder people there.
- Red. Bruce Willis' character is sneaking into a CIA file room that's so secret most agents don't know it exists. He gets into the elevator and presses the bottom button marked P2, holding his finger there as the floor indicator goes past that number to P3, B1 and finally B2 before the doors open.
- Hidden Floor, a Korean horror film, takes place in an apartment building haunted by spirits that dwell on the supposedly non-existent fourth floor.
- There are several missing floors in Mirage (1965):
- On his way down the stairs of the Unidyne building (Manhattan), the hero notices that the 13th floor is missing. His Love Interest remarks that this is because the natives are superstitious.
- Later the hero uses a special key to get to the Major's office on the otherwise inaccessible 65th floor.
- There are four other missing floors. At the beginning the hero chases a woman down the stairs in the dark (the power has been shut off) and goes down four sub-basements to emerge in the boiler room. Later those floors aren't there. He has amnesia but doesn't know it yet. Those four floors below ground is where he worked in a lab in California. It's a random memory.
- In the short story/prose poem "E is for Elevator People", author Harlan Ellison describes certain elevators via which, if you accidentally press the Basement button too many times, you are taken down to "the caverns". Awful things happen there.
- The Wayside School book series takes place in a 30-story school building. (It was supposed to be one story, with thirty rooms... The builder was very sorry.) Mrs. Zarves teaches on the 19th floor. The nineteenth floor doesn't exist. How can that be? The builder forgot to include it. Each book is thirty "stories" long, and in each book the nineteenth story is about Mrs. Zarves.
- In the first book, the nineteenth chapter is simply "There is no Mrs. Zarves. There is no 19th story. Sorry."
- In the second book, one character Lampshades this and wonders why the numbering isn't just shunted down after floor 18. She ends up stuck on the nineteenth story for three chapters, which are naturally chapters 19, 19, and 19. While there, she meets students that other characters made up in previous chapters. The next chapter fixes the numbering by being "Chapter 20, 21, & 22".
- In the third book, the nineteenth chapter features Mrs. Zarves complaining about never being noticed, as well as a cow who won't leave her room (which is a Call-Back to the beginning of the book).
- In Mirror Dance by Lois McMaster Bujold, the Durona Group has a set of secret subbasements (in which they store the protagonist while they're resurrecting him after cryogenic suspension).
- Platform 9¾ from Harry Potter is a variation, accessed by walking through the barrier between platforms. 12 Grimmauld Place (the Black family home) could be considered the street address version of this trope, as the house at that address is only visible by magic.
- Level 13 of The Hitchhiker's Guide to the Galaxy building in Mostly Harmless is hidden. Ford is so used to Earthly superstition that it takes him a moment to notice this. It turns out to be where the sinister new Guide is being made.
- Ogden Nash wrote a poem "A Tale of the Thirteenth Floor" in which a would-be murderer gets into an old-fashioned elevator, with an operator, in a hotel. The operator chooses to stop at the 13th floor — to show him murderers chained to the corpses of their victims in a ghastly dance of damnation. (The whole hotel is kind of hellish, but the 13th floor is true Hell). The point is made, the plan abandoned.
- In Stalking the Unicorn by Mike Resnick, every building in New York supposedly has one of these for its 13th floor, reachable by climbing stairs in the surrounding floors in an elaborate sequence ("It depends on the weather and the day of the week.").
- In the children's book The Thirteenth Floor, the building is supposed to be one of the ones where the numbering just skips from 12 to 14... but when the protagonists manage to get into the thirteenth floor, it turns out to be a Time Portal.
- The War Against the Chtorr. The Uncle Ira Group is located on the 13th floor of a hotel in Denver, reached by a private elevator. The first-person protagonist mentions that "controlled-access architecture" is nothing unusual in this 20 Minutes into the Future world, as hotels use them for guests who need extra security and privacy. You'd only realise it was there if you walked the fire stairs, and if asked the hotel would claim it was a service floor. They just wouldn't mention what service.
- In the Necroscope saga by Brian Lumley, the ESPionage group E-Branch has their base on the top floor of a hotel. Although people working at the hotel — and anyone who cared to count the hotel's floors, go inside, and ask for a room on the top floor, and look at the floor number — know that there is a top floor, it has its own elevator and fire escape, and is stated to belong to a group of "International Entrepreneurs"note .
- The home base of the Moscow Night Watch is in a hidden floor, not normally accessible and not noticeable from the outside by non-magicians.
- In the Percy Jackson and the Olympians series, Mount Olympus is accessed through the 600th floor of the Empire State Building.
- In the Star Trek: A Time to... series, the Federation embassy on Qo'nos has a secret subbasement.
- In book 7, A Time to Kill, Section 31 has a listening post there. The listening post is moved elsewhere after Ambassador Worf visits it; although he's the Federation ambassador to the Klingon Empire post-Deep Space Nine, he isn't supposed to know about the post.
- In book 9, A Time for War, a Time for Peace, Worf puts the now-empty subbasement to good use as he retakes the embassy from a Klingon terrorist group.
- Fire World, the sixth book in the Dragons (a.k.a. Last Dragon Chronicles) series, features a massive Librarium, in which the only way to navigate between floors is to imagine your destination. Floors beyond the 42nd floor are inaccessible to all but the very best.
- The Day of the Jackal. The OAS leaders hiding out in a hotel in Rome create one by renting the top floors and welding shut the lift doors on all but one floor, which is guarded by their men.
- In Angel, the "White Room" in Wolfram and Hart is accessed by pressing a specific set of buttons in the elevator.
- In the eponymous Are You Afraid of the Dark? episode, the thirteenth floor exists, but its occupants have long since disappeared. Turns out that the former residents are aliens, and they're coming back for their daughter, Karin.
- The last season of The A-Team had an episode where Murdock is infiltrating a mental hospital. He and Hannibal discover a secret floor because the elevator takes longer than usual to go between particular floors.
- In an episode of The Avengers a hotel actually has an unlisted 13th floor which is used to capture and brainwash scientists. No one expects there to be a 13th floor so they don't suspect there are two "12th" floors.
- On Babylon 5, all the levels in sector Grey beyond 16 are mislabelled, with Grey 17 actually being the 18th level and so on. The actual 17th level had been sealed off during construction of the station and the elevators programmed to stop according to the new numbering system. Since sector Grey consisted entirely of the station's industrial facilities that were only visited by maintenance crews, it took four years before anyone noticed that the elevator takes twice as long to get from level 16 to 17 than between all other levels. The hidden level was used as a hideout by a doomsday cult who sealed themselves in with an alien monster.
- Doctor Who:
- "The Runaway Bride": The elevator of the H.C. Clements building has a button for the "Lower Basement", which is curiously absent on the official floor plans.
- In a rare example involving stairs instead of an elevator, in "The Lodger", people who go up the stairs to the second floor loft above Craig's flat tend to disappear. When Craig's best friend/secret crush Sophie visits the second floor loft, Craig and the Doctor follow her. Meanwhile, Amy (who is stuck in the TARDIS outside of space and time) contacts the Doctor and informs him that she was able to find the plans for Craig's apartment building. "There is no upstairs!" Turns out there was a spaceship parked on top of the building, disguised as a second floor and using a Perception Filter so people wouldn't notice the building only used to have one floor.
- Dollhouse. Agent Ballard locates the building containing the Dollhouse, but after going on site can't find anything suspicious. So he does some research and discovers that in addition to the usual contractors the builders hired an environmental systems consultant, an expert in buildings that recycle their own air, water and power — which you'd need for underground floors that you're trying to keep secret from anyone else in the building.
- One I Dream of Jeannie episode has the main characters attempt to book a room in a filled-up hotel, so Jeannie just magically creates a 13th story and books the room there, when the Bellows know that the hotel in question only has twelve floors. Cue much confusion from the hotel staff and the Bellows, while Tony and Jeannie simply denied that there was anything unusual about the floor at all.
- Person of Interest. In "Dead Reckoning", the 21st floor of a building can only be accessed by pressing a combination of buttons in a particular elevator. It turns out to be a secret Department of Defense facility for cyber warfare.
- The Pretender has sub-level 27, which became a major focal point for the series — as it progressed, it became hard to find anything that wasn't a result of something that happened on SL-27.
- Although strictly speaking almost everything in the Centre took place on 'missing floors'....from the outside the Centre was just a few stories tall, but it had 27 floors underground. The part above ground was used for counseling and legit psychological testing, and the basement sublevels were used for all the illegal stuff. It's just that SL-27, the very bottom sub-level, was even secret from most of the people who worked there.
- In Red Dwarf, Floor 13 is believed not to exist by most of the crew. It houses the ship's brig and is accessed by using a key to reveal a secret panel in the lift.
- The Rockford Files episode "Sticks and Stones May Break Your Bones, But Waterbury Will Bury You".
- Smallville has a fertilizer plant with a hidden sub-level 3. The 3 button on the elevator is invisible. More specifically, its a black marble button in a black marble control panel.
- The Twilight Zone (1959):
- The episode "The After Hours" has a 9th floor in a department store that's less than 9 stories high. It's where the store mannequins hang out when they're waiting to have their month out among living people.
- The Devil has a travel agency on the 13th floor in "Of Late I Think of Cliffordville".
- Deus Ex gets a Wham Episode moment out of revealing that the secret Majestic-12 prison you've been trying to break out of is, in fact, the restricted-access-only bottom level of your employer's headquarters.
- Silent Hill
- The fourth floor of Alchemilla hospital.
- Similarly, in Silent Hill 3, after the phone call in the hospital, you go through a Missing Door that wasn't there before, that leads you to the alternate hospital.
- Several floors of the Office Building in Silent Hill 3 only exist, or at least can only be accessed in the Dark World. The sixth floor is not accessible at all.
- The Evil Brookhaven Hospital in part 3 has three basement floors (two of which don't exist in the normal world), but only B3 is accessible.
- The thirteenth floor in the Macintosh Doom clone Sensory Overload has no button in the elevator, and can only be accessed via ventilation ducts. Beyond that is the sub-basement, only accessible via the hidden express elevator in the Big Bad's office.
- The Journeyman Project: "Access denied. This floor is neither modeled nor rendered."
- In the forgettable 1994 adventure game Hell Cab, pushing a red button on the elevator in the Empire State Building would take you down to hell.
- In Ghoul School for the NES, the left half of the school can only be accessed via the roof. To get there, you must get on the elevator, press up, and hold it down, at which point the elevator will shake as though resisting, then rise to the unmarked ceiling. There's no indication that you need to do this.
- Tower of the Sorcerer has three. The first one is obvious, since the stairs from floor 42 go direct to floor 44. The intervening floor 43 can only be accessed by obtaining the "wings to fly up", which move you up one floor wherever you use them. There are also "wings to fly down", and one puzzle depends on using these to access floor 0. Finally, the floors come in groups of ten, but the highest floor accessible by stairs is floor 49. There is a floor 50, which you reach during the game's ending.
- In Space Quest II, the elevator in Vohaul's space station has no 2nd floor button. To reach that area, you must solve a gauntlet of puzzles that require items from the other floors.
- In Grim Fandango, Maximino's High Rollers' Lounge has an extra floor between its main area and the wine cellar. You need to figure out how to stop the kitchen elevator at the right point in order to get there. Also you can't Sequence Break by getting in there before you know about it.
- In Outlast the main elevator can descend to a secret floor where the Morphogenic Engine experiments are carried out.
- Appears in S.S.D.D, where a supposed "storage installation" in the middle of the desert hosts a top-secret research-lab in a hidden basement. Once again, it can only be accessed by hitting the elevator buttons in a specific order. Or by blasting the panel, apparently.
- In Thunderstruck, every building that goes from 12 to 14 in their numbering still has a metaphorical 13th floor. Which a mage can enter and walk around in. Makes for a good place to stash your Doomsday Weapons.
- On We're Alive, the Tower is stated to be 15 stories tall but its really only 14 because there is no thirteenth floor.
- Whateley Universe likes this one; all the cottages have at least one hidden basement floor, where they keep the exercise equipment and cottage vaults that Muggles shouldn't see or have access to, and the required display is hidden as well (because, after all, you don't want people just walking in and seeing that you've got several tons of gold just sitting around). And that's not even counting the hidden tunnels, and laboratories and workshops, and the testing areas that are all buried underground, too. It's Lampshaded in mentions that they have to be very careful about where they tunnel these days, or risk sections of the school falling into a sinkhole.
- A Freaky Stories story has an obsessive man trying to figure out the secret of a building's 13th floor. When he finally gets to it, he finds that the door to the 13th floor locks from the inside, trapping him with everyone else who had discovered it.
- Kappa Mikey has a secret floor in Lily Mu Towers, which is accessed by pressing the buttons 9 and 4 (9+4=13). It is home to a mad scientist (who, according to Ozu, hasn't paid rent in 40 years).
- This was used to great effect in an episode of The Real Ghostbusters, when Janine dons her 5th Ghostbuster gear to track down the missing quartet. She traces them to a building, but can't find them anywhere within it. When she rides the elevator, she notes the missing thirteenth floor but dismisses it as superstition, until she notices that it takes too long to go from floor 12 to floor 14. One emergency stop button and one proton-pack charged "lock-pick" later and she's found a ghost floor, complete with ghost receptionist.
- Truth in Television, sort of: some buildings actually do omit floor number 13 or floor number 4 (the latter in Japan and China, since Four Is Death there). This is just a renumbering to cater to the superstitious, though: the floor isn't missing, the number is.
- Some Chinese buildings go as far as to skip any floor number with 4 in it — having the effect that you can buy a 50th-floor Chinese apartment in a 36-storey building.note
- Due to its history, Hong Kong buildings can occasionally defer to BOTH superstitions. The result? Well, see the photo at the top of this page. (yes, that particular elevator is in Japan, but it's more common to see 13 skipped in Hong Kong)
- This custom makes it a little more convenient for fictional entities wanting to make a "real" missing floor – since no-one expects to visit a floor numbered "13", they won't be surprised when the ordinary everyday elevators skip by that floor.
- Many skyscrapers have dedicated mechanical floors used for heating/cooling units, electrical junction boxes and maintenance equipment storage. The horizontal bands on the former World Trade Center towers were a visible example. These types of floors are not typically accessed from the main public areas but usually count in the floor numbering. Of course, 13 is a popular choice.
- This is quite common in Moscow. Because button panels were manufactured in a limited variety of sizes, elevators would often be installed with panels with more buttons than necessary. For example, in some buildings with ten floors only nine of them are served with the elevator, while the panel in the elevator has 10 buttons, however.
- Moscow State University's Main Building has several 'tech floors' which are hard to get in (not mentioning top floors with restricted access). There are also underground tech rooms between Main building, Chem Building and Phys Building for sure and urban legends exist about even more hidden undergrounds there.
- Many building from USSR times in Moscow have bomb shelters with hardly available entrance.
- The Mount Auburn Hospital in Cambridge, MA has no sixth floor in its main wing. Or at least none that can be easily gotten to – none of the public elevators go to it, and its door is locked from the stairwell. It's mostly maintenance and engineering stuff.
- In a subversion of this trope, back in the 1980s and 1990s, the elevators in Cincinnati and Hamilton County Library's Main Library building had floors numbered A, B, 1, 2, C, D, 3. Only the numbered floors were accessible to the public. The lettered floors were for the stacks. (There were also references in the building to a floor "M" (for Mezzanine) between the first and second floors, but it was only accessible via stair or wheelchair ramp.)
- At the main station at Hannover in Germany the departure platforms 5 and 6 are nonexistent. However there is a rather unspectacular explanation for this: Track 5 and 6 are solely used for the transport of goods, and because of that a platform is unnecessary.
- Some subway stations in New York and London have non-existent (or Dummied Out) platforms.
- As do some surface stations; Stratford Regional has no platform 7. In general, it's because renumbering a platform requires the signalling system to be redesigned, and it's much simpler just to stop using the number if the platform closes. Thanks to repeated rebuilds of Stratford, its platforms are now numbered in the order 4A,4B,3A,3,5,6,8,9,10,10A,11,12,2,1, with 13-17 in a group on their own.
- for this reason, Edgeley Station in Stockport has a Platform Zero and not a Platform Five.
- Terminals at John F. Kennedy International Airport in New York are numbered 1 through 8. Each terminal was intended to be used by a specific airline. 3 and 6 are skipped, as their primary tenants (Pan Am for the former, TWA and JetBlue for the latter) had eventually gone out of business and were subsequently demolished to allow other terminals to expand.
- Relatedly, sometimes subways and other rail networks have "missing" stations.
- During the Cold War, East Berlin had a number of "ghost stations" (Geisterbahnhof) in places where U-Bahn and S-Bahn lines originating in West Berlin would briefly pass through East territory. Trains would pass through without stopping, and many of these stations remained deserted and unchanged from 1961 to 1990. The term "ghost station" remains in common use for stations that are closed, but have not been demolished.
- Philadelphia's rapid-transit network has two "ghost stations": Spring Garden Station on the little-used SEPTA Broad-Ridge Spur, and Franklin Square Station on the more-used PATCO line between Center City and New Jersey. The Broad-Ridge Spur is so little used that there's little chance Spring Garden will reopen, but reopening Franklin Square is an idea that is periodically floated, considered, and then withdrawn. (As of PATCO's December 2014 agenda, it is being considered.)
- Then there's the oddity of the U-Bahn having a line 1, 2, 3, 4, and 6 but no 5...
- The New York Subway has ghost stations, too, including several that were closed due to the lengthening of platforms at adjacent stations. A number of them are also still intact, but trains don't stop there.
- For decades during the Cold War there was a secret bunker beneath a wing of The Greenbrier resort in West Virginia, built in order to house the U.S. government in the event of nuclear war.
- It's common for ships not to have a deck numbered 13 – maybe to cater to the superstitious clientele, maybe due to the traditional superstitiousness of sailors.
- In Brazil, there is a TV station/college building (the Gazeta Building) that actually has a Floor 3½. It can only be reached by one of the stairs, and no elevator stops there. Disappointingly, the only things on that floor are a few ATMs and a small bank agency.
- A building in Rotterdam, used by Dutch insurance company Nationale Nederlanden, has several of these. Certain elevators do not have a 1st or 2nd floor (ground being 0th in the Netherlands) because the entrance hall is three regular floors high, and some of the building's towers have service floors only accessible by a special separate staircase. Makes for fun times for an engineer who needs to service something but is unfamiliar with the building's layout.
- O'Hare International Airport in Chicago has four terminals, numbered 1, 2, 3, and 5. They skip Terminal 4.
- An explanation for this: Before the 1980s, there were just three terminals at O'Hare - Terminals 1, 2 and 3. Terminal 1 was for international flights and the other two terminals housed domestic airlines. However, in 1985, the original Terminal 1 was demolished and replaced by the current one (which today is used for United Airlines flights). So while the new United terminal 1 was being built, and until the current International Terminal opened on the east side of the airport, a temporary "Terminal 4" was erected on the ground floor of the main parking garage. International passengers would check in for their flights there and be taken directly to their aircraft by bus. It was used from 1984 to 1993 prior to the opening of Terminal 5 as the International Terminal. There is rumor that Terminal 4 might return if expansions and increases in air traffic at O'Hare justify the need to build additional terminals.
- Another example from O'Hare is in the concourse letters: they have concourses B, C, E, F, G, H, K, L, and M. There actually used to be a Concourse D at O'Hare (which can be seen here◊), which was used by carriers like AirCal, Braniff, Continental, Eastern, Northwest Orient, Piedmont and United Express, but it was demolished as well to make room for the current Terminal 1 concourses. ORD, however, has never had a Concourse I or Concourse J.
- Almost all airlines have seating algorithms where certain seat row numbers are skipped. Some noticeable instances:
- On all narrowbody United Airlines aircraft, some row numbers in the forward section of the Economy cabin are skipped so that rows 20 and 21 are always the numbers used for the overwing emergency exits.
- Lufthansa's Boeing 747-8 planes have two major number skips: First Class and Business Class on the main deck are rows 1-11 or -14. Then there's a skip to row 16 or 22 at the front of the Economy cabin. However, Business Class is actually split between the main deck and the entirety of the upper deck. The upper deck Business Class seats are numbered rows 81-88. Economy Class on the main deck ends at row 49, so there's a big number skip.
- Toronto Pearson International Airport has two terminals: terminal 1 and terminal 3. The former terminal 2 was replaced by a pier for Terminal 1 and was primarily used for transborder traffic to the United States.
- The former Hotel Alexandria in Los Angeles has a "ghost wing" that was sealed off due to a rent dispute in 1938, and no elevators or stairs were built in that wing. While the lower and top floors can be reached from nearby rooftops, floor 3 through 6 remain completely inaccessible.
- Box Hill train station in Victoria, Australia, has platforms 2, 3 and 4. Platform 1 for whatever reason has been made inaccessible from the shopping center, and has had its tracks stripped.
- Similarly, for many years the platform numbers at Clapham Junction in London started with 2, after the 'banana arches' supporting the trackbed for Platform 1 became structurally unsound. It now has a new Platform 1, created by splitting Platform 2 in half; if the original platform 1 were to be repaired, it would have to be numbered 0.
- Boston's Logan International Airport has terminals A, B, C, and E, but no D. Well... Terminal D technically existed, but to all intents and purposes it was just a set of three gates in a nondescript wing of Terminal C, so in March 2006, they were renumbered and labeled as part of Terminal E (E1C, E1D & E1E) on February 28, 2006. In 2016, following construction of an airside connector between Terminals E and C, these three gates were renumbered again to become the present gates C8-C10 (as part of Terminal C).
- Phoenix Sky Harbor International Airport in Arizona has terminals 2, 3, and 4, but no 1. Terminal 1 was torn down in 1991 and replaced with a parking lot, but the others kept their numbers because of familiarity.
- During their initial expansions in the 1970s, Breckenridge Ski Resort in Colorado used letters and numbers for their chairlifts. Skips in the numbers/letters exist due to some of these lifts getting replaced, as the replacement lifts have used names.
- Fixed grip chairlifts on Peak 9 are lettered. At one point, there were Lifts A, B, C, D, E, and F. Today, only Lifts A, C and E operate. Lift Fnote was converted into a high speed quad and renamed the Falcon SuperChair after just a year of operation, Lift Dnote was replaced by the Beaver Run SuperChair in 1990, and Lift Bnote was replaced by the Mercury SuperChair in 1997.
- Originally, fixed grip chairlifts on Peak 8 were numbered. There was a Lift 1, Lift 2, Lift 3, Lift 4, Lift 5, Lift 6, and Lift 7. Only the last three are still around: Lift 1note was replaced by the Colorado SuperChair in 1986, Lift 2note was removed around 1997 due to lack of use, Lift 3note was removed around 1980, and Lift 4 was replaced by the Peak 8 SuperConnect in 2002.
- The city of Vancouver is averting this trope. A law was passed in 2016 that bans new towers from omitting floor numbers so there's no floor 4, or 13, or what have you. However, existing buildings can keep their oddly numbered floors.