A Memory Palace is used to explore a character's memory as an actual organized (albeit non-physical) space. Often, the palace owner may use it as a method of retrieving a needed memory, which may involve a Journey to the Center of the Mind.
The concept comes from the real-life Method of Loci (Latin for "places"), a mnemonic technique dating back to ancient Greece, involving associating memories with specific images and organizing them at fixed points in one's mind.
A subtrope of Mental World, which often involves memories, dealing with the actual spaces representing said memories (which are intentionally built by the character's mind). If the memories are unpleasant, the palace may become a Black Bug Room.
Compare Pensieve Flashback.
- In The Dresden Fillies when Harry accidentally soulgazes Twilight, this is how her soul appears to him, in a castle/library flavor.
- Inside Out: The seat of Riley's personality is a large building in her mind called "Headquarters," and each of her "core memories" is used as a basis of a floating island in her mind that represents a significant personality trait. As Riley's mental state worsens and her core memories get lost, the islands begin to crumble.
- In The Cell, Carl Stargher's mind is portrayed as a dark, twisted maze. One section is a rotting house that contains memories of his abusive childhood. He also stores the memory of his first murder there.
- Inception shows an involuntary version. Trained memory extractors build dream constructs for their targets, who automatically store their secrets and memories in them. The extractors then infiltrate the construct and steal the information they want. The palaces are designed to be complex locations, everything from houses to hotels to a fortified mountain fortress.
- Cobb builds a classic one to process his grief and guilt over his wifes death. Painful and important memories are stored on levels accessed from an elevator.
- A memory palace is used for mental combat in Doctor Sleep. Rose The Hat projects her mind into that of Abra, a psychic girl, while she sleeps. Seeing her memories as a series of filing cabinets in her bedroom, Rose tries to open them... Only to find herself trapped as Abra speed-reads through Rose's memories instead (Rose's palace is shown as a huge library signifying her ancient life).
- Dreamcatcher: Jonesy keeps his memories in a messy warehouse. It becomes a plot point when his body is hijacked by an alien entity, trapping his mind inside it.
- In The Dark Tower, when Roland reaches the titular Dark Tower, he finds a series of rooms depicting events in his life, most notably Roland's companions killed in his quest for the tower, beginning with his hawk David.
- In the Thomas Harris novel Hannibal, Dr. Hannibal Lecter is a master of a vast memory palace, portrayed as an elegant mansion. It's mentioned that he would spend years inside it while incarcerated in an insane asylum.
- Briefly shown in a later Harris novel, Cari Mora. The antagonist, Hans-Peter Schneider, mentally visits his "memory rooms" and stops by a large walk-in freezer where he keeps his parents; as a child he locked them inside it to freeze to death.
- In the original Arthur Conan Doyle stories, Sherlock Holmes referred to his brain as an attic.
- Lazarus Long uses the technique to organize his mind once his life has stretched centuries beyond a normal human lifespan. He describes it as the only way to stay sane with the expanse of time his mind must process. He laments that it doesnt always work, as he once found himself searching for where he left the book he was reading, only to remember he was reading that book 50 years ago.
- Agent Pendergast has an elaborate palace built in the memory of his family estate. He uses the knowledge stored there to solve his mysteries.
- In the first episode of the Finnish detective series Bordertown, detective Kari Sorjonen explains the memory palace concept, and, throughout the series, he marks rectangles with tape on his basement floor where he stands to imagine himself at various significant loci in a case, organized into memory palaces.
- Dispatches From Elsewhere: Fredwynne uses the memory palace technique by name to recall clues and details about the game, represented by him watching a bank of television monitors on a wall; he later teaches Janice to access hers, which starts as an empty space because, as Fredwynne explains, she hasn't learned to organize her thoughts for easy access.
- The Librarians: In the episode "And The Echoes of Memory," Eve tries to hold on to the Library's memories by constructing a mind palace, focusing on three specific items: the Spear of Destiny, the golden lions at the entrance, and the Ark of the Covenant. Eventually, though, she finds that the items are slowly disappearing from the palace, until she can no longer remember anything. Flynn does the same, except he uses a String Theory hidden behind the padded walls of his room to aid him.
- Sherlock: Holmes uses his "mind house" to store information when using his deductive techniques. Rather than being represented by a building or room, it's viewed as a digital layout of maps and words when he needs to access his memories while on the go, and sometimes has mental representations of people he knows advise him. When he has more time he uses mental rooms and hallways, but even there his thinking consists of people and dialogue.
- In the episode "His Last Vow," Sherlock attempts to entrap an extortionist, Charles Augustus Magnesson, into revealing his blackmail archives so Sherlock can have him arrested; the detective is dismayed to learn Magnesson keeps the archives in his own memory palace (not shown onscreen but described as a vault), and with no physical evidence he is safe from prosecution. Unfortunately for Magnesson, when he makes the incredibly stupid mistake of threatening John, Sherlock decides to destroy the vault anyway.
- An interesting version in Westworld: The Forge is a digital data facility used as part of an experiment to copy human minds into hosts; the memories of the park's guests are downloaded and stored there. When Bernard and Delores enter, they find both a library containing all the downloaded memories (in the form of books written in computer code), and three-dimensional constructs (such as James Delos's memory of the last time he saw his son, Logan).
- In Mario & Luigi: Bowser's Inside Story, Bowser's brain (called the Memory Banks) is revealed to be a library of various memories stored in book shelves and maintained by a single Globin. The Mario Brothers travel inside his brain to search for the safe code that he can't remember due to recent head trauma, but upon arrival, the Globin scans the Bros and considers them a threat, transforming into blocky versions of themselves to fight them off. After the Bros defeat them, the Globin reveals that the memory containing the safe code got shattered and needs to be put back together. The Bros succeed and Bowser remembers the code, gaining access to the second Star Cure.
- Steven Universe: In "A Single Pale Rose", Pearl has Steven go inside her gemstone to get her phone, and Steven finds himself in a void with only another version of Pearl and all the items stored in her Gem. It's implied that other Gems have their various selves running around freely within their Gemscape, but because of all her... unsightly memories, Pearl compartmentalizes hers, making it so you have to find that layer's Pearl and ask her to take you deeper. This results in each of the Pearls having an area that resembles the particular memory they come from.
- The Mighty B!: Bessie searching through Ben's memories is represented by her entering a room full of file cabinets that display memories in a similar fashion to a film camera.
- SpongeBob SquarePants: In "The Inside Job", Plankton goes inside of SpongeBob's brain to try to find the Krabby Patty Secret Formula, the interior of which is a recreation of his home. All of SpongeBob's memories are stored in a file cabinet in the recreation of his library, with each memory being a folder that will trigger a sound or action when opened. Plankton is unable to find the formula however as a note in the cabinet tells him that it is located in the heart.
- Ed Cooke, a World Memory Champion Competitor, describes to Josh Foer in his book Moonwalking with Einstein how he uses the method of loci. First, he describes a very familiar location where he can clearly remember many different smaller locations like his sink in his childhood home or his dog's bed. Cooke also advises that the more outlandish and vulgar the symbol used to memorize the material, the more likely it will stick.