Locked in the Dungeon

A dungeon is a secluded place, often underground, where criminals or innocent victims alike are taken for corporeal punishment or, ahem, "questioning". Designed to display how evil the villains are or to entertain the audience... or both. Depending on the setting, expect the torturer to be a thug, a Dominatrix or an Exalted Torturer.

Common in medieval settings and spy stories. Expect our heroes to escape from one at least once, even in video games where they are strong enough to beat down the guards when you finally fight them. Unless it's that kind of story, in which case escape is impossible but probably not wanted anyway.

The heroes may occasionally be thrown into the dungeon because they are falsely accused of a dangerous crime. If so, expect a jailbreak attempt.

Compare Torture Cellar, for more modern examples. Only loosely related to Dungeon Crawling, where "Dungeon" refers to a monster-filled area in Tabletop Games or Video Games.

Examples of Locked in the Dungeon include:

Anime and Manga

In one episode of Black Butler, Sebastian is locked in a dungeon where the crazy Angela is prepared with her own sleazy torture-monger to extract information out of him and to convince him to join her side to destroy Ciel.

City of Dreams has "The Tower of Atonement" where people are taken to be whipped et cetera for whatever mischief they have done.
In one Deadpool adventure, our hero gets chained up in a dungeon to be eaten by zombies. Being the person he is, he have only one thing to say about his situation: "SAFEWORD!!!"

You Can't Do That on Television had a recurring sketch with one of the kids in this situation (no torture shown, of course). The commandant from the Firing Squad sketches often offered them freedom, but some terrible price.
Merlin, repeatedly.
The kidnapper in Strong Girl Bong-soon does this with the women he's abducted, in what appears to be a functional jail built under the business he owns.

In the movie Labyrinth, Hoggle and the girl are taken to an "oubliette", which Hoggle describes as a place where one puts prisoners who are to be forgotten.
The Princess Bride had the Pit Of Despair, where Wesley was tortured to mostly death.
The Man in the Iron Mask was kept in a dungeon until he was released by the musketeers.
The Inquisition scene in History of the World Part One would be a subversion. Fairly standard dungeon: people in shackles, getting tortured, etc.... And then everyone breaks into song.

Harry Potter subverts the concept of Dungeons. Some Hogwarts dungeons are classically dungeon-ey, and some serve as Potions classes (mind you, this setting is dangerous if the potions being brewed there may be explosive if not done correctly).
- Note that most Real Life high schools have the chemistry lab(s) on the uppermost floor of the building.
In The Silmarillion, Beren, Finrod Felagund and their followers were locked in a particularly horrific Dungeon and eaten one by one by a werewolf.
In Slave World, every aristocratic mansion or castle comes with a dungeon block for the slaves.

Castlevania games often include a dungeon area.
In The Legend of Zelda Twilight Princess, after Link gets turned into a wolf, he wakes up locked in a dungeon inside Hyrule Castle.
- The Shadow Temple in The Legend of Zelda Ocarina of Time has some elements reminiscent of a dungeon as well, such as chains, prison cells, and torture devices.
In The Elder Scrolls IV: Oblivion, you can be locked in one of these for crimes. You have a choice: serve your time and lose some skills, or attempt an escape.
In EverQuest, Highpass Hold has one of these in the basement. Complete with mad prisoners, a Dark Elf dominatrix and her poor suffering male High Elf victim.
In Dungeon Keeper II, you are encouraged to build a dungeon in your dungeon. that is, a dungeon of this kind inside the "heroes come here to kill monsters" kind of dungeon.
In Quest For Glory II: Trial By Fire, you are captured and put in a dungeon with a recently tortured Hero of Another Story. 10 seconds later, you escape together.