Hostile Architecture

[Worldbuilding] d20 Fantasy Settlement Landmarks

It's nice if the settlements in your setting have something for you to identify them with and for players to remember them by. It enables you and your players to tell places apart from each other, so that they are not traveling from Generic Big City A to Generic Small Village C.

A landmarks sticks in your players' memories of a place when you feature it in your decription on first arrival and briefly mention it again whenever the players return. "The great white tomb that so brightly rose above the village when you first visited at the start of summer, now looms large and depressing in the autumn rains." That sort of thing. You'll figure it out.

d20 Landmark Further details
1 Tomb Is it a large structure (Great Pyramids of Giza, Mausoleum at Halicarnassus, Taj Mahal), or small and humble? Is it one tomb or many (a sprawling graveyard, a necropolis)? Who does it hold (a hero, a prophet, an angel or demigod, a villain, a celebrity, a mage, a monster, a pet)?
2 Hill figure or geoglyph Does it depict something concrete, such as a man, a beast, a monster, a specific person, or an event (Atacama Giant, Uffington White Horse), or is it something abstract (Nazca Lines)?
3 Waterfall Is it very large, thin and tall, low and wide? Stepped, or one big fall? Is it roaring and dangerous, or inviting? Is it mundane or is there something magical about it (a naiad's home)
4 Tower Is it a lighthouse (Great Lighthouse at Alexandria), a prison (Tower of London), a mage's tower, a fortification, or a home?
5 Colossal remains Are they integrated into the architecture of the place (homes built in titan skulls, great serpent bones arching over the bazaar)? Are the remains banal, grotesque (crucified giant) or oddly enchanting?
6 Statue Is it one very large statue (Rhodes Colossus, Leshan Giant Buddha) or many smaller ones (Moai)? Does it depict a person, monster, beast? Is it supernatural (people petrified by a medusa or local basilisk, a living sculpture)? Is it the avatar of a god (Statue of Marduk)?
7 Rocks and geology Is it part of the landscape (White Cliffs of Dover) or an object people interact with (Húsafell Stone)? Did people change it? Is it one thing (monolith) or many (standing stones, Stonehenge)?
8 Hot springs Is it dangerous (boiling lake), strange (Grand Prismatic Spring at Yellowstone), or safe for bathing? Is there a bathhouse present, large (Széchenyi Medicinal Bath Budapest) or small and rustique (sentō, sauna)?
9 Scars or badlands What happened to the land that scarred it? Was it natural (meteor, volcanic eruption) or unnatural (magic rift, battling gods)? What did it leave behind (crater lake, canyons, jagged towering spikes of glass)?
10 Industry What does it produce? Is it extensive, altering the landscape (quarry, forestry) or visually striking (smokestacks from iron smelters, large manufactory halls, one or more waterwheels or windmills)?
11 Stronghold Who does it defend against, outsiders or the townsfolk? Is it purely military (fortress) or also a place for living, like a castle or palace (Alhambra)? Is it an extensive complex (Forbidden City), or rather simple (a fortified mansion)? Is it inhabited by rulers, garrisoned by soldiers, or squatted by commoners (Diocletian's Palace, 7th century CE) or occupied by rebels/bandits?
12 Community space Is it a building (mead hall, longhouse) or an open space (plaza, like Moscow's Red Square)? Is it used for politics (forum), commerce (bazaar), to accomodate travelers (inn, hotel), or bureaucratic (town hall)?
13 Religious Is it a place of worship (temple), a seat of power (cathedral) or a place of contemplation (monastery)? Does it attract pilgrims (how many, what kind)? How does it influence the townsfolk and economy?
14 Academic Is it grand (university campus) or simple (a clearing in the woods)? What subjects does it teach (magic, engineering, warfare, dueling)? Is it local or (in)famous? Are the students intertwined in life in the settlement or do they keep to themselves?
15 Supernatural Is it dangerous (a well of hungry ghosts) or useful (an everburning furnace)? Does it create opportunities (a stable portal to another realm) or chaos (a magical rift that flares up in unpredictable ways)? How did it come to be?
16 Flora Is it natural (an ancient oak), supernatural (a colossal Tree of Life), or man-made (a botanical garden)? Does it provide food, shelter, jobs? Or does it overgrow everything, is it a nuisance, a plague, a danger? What lives in it (people, animals, monsters, spirits)?
17 Labyrinth Is it organic (a hedge maze), artificial (Cretan Labyrinth) or magical (a sentient everchanging maze)? Is it for pleasure (strolling, games, romance)? Or is it made to keep something in (the Minotaur) or out (unwanted guests)?
18 Monument Is it large or small (stele)? Simple and plain or heavily decorated (Trajan's Column)? What is its shape (arch, obelisk, pillar, slab)? Does it commemorate a single event or many (Black Obelisk of Shalmaneser III)?
19 Sports Which sports are played here? Is it mainly for participants (Palaestra at Olympia) or for spectators (a stadium or arena, like the Colosseum)? Is there a famous local or regional competition? Is there a champion who can be challenged?
20 Roll for two landmarks This town is so nice, you remember it twice

Other general questions you can ask to add details to the landmark and make it something unique:

Feature Questions
Aesthetics Is it beautiful, inspiring, ugly, funny, ominous, dangerous, foreboding? What is its effect on the local atmosphere? Does it change with the weather/season?
Age Is it old, perhaps even older than the settlement itself? Or (relatively) new?
Creator(s) Is it known who made it or where it came from? Was it an ancient progenitor, a famous artist, a local talent, an occupying army?
Dungeon Is it a place the PCs can delve into and explore for money, fame, magical loot, etc.? What dangers does it hold that are unique to it?
Material Is it made from a special or rare material, like volcanic glass, black marble, cold iron, bones, etc.?
Owner Is it owned by someone (a duke, the town council, a guild) or not? Do they actively use it or live there?
Resource Is it tied to a certain resource? A local foodstuff or drink, a crop or material, arcane fuel, crystallized curses, secret knowledge? Does it consume or produce the resource? Can the PCs obtain it here (for a price) or deliver it (for rewards)?
Relationship to the people Is it beloved by the people? Hated? Feared? A source of pride? Or largely ignored?
Relationship to the settlement Is it located within the settlement or outside it? Was the settlement build around it or even because of it? Is it so big the settlement is inside of the landmark instead of the other way around?
State Is it fallen in disrepair, half-ruined, or well-maintained? Who takes care of it?
Tradition Is it tied to certain traditions (annual town fair, weddings, burials) or customs (making warding signs towards it, asking it for blessings, rites of passage)?
Use Is it still in use or (largely) abandoned? Does it have a purpose currently? Did its purpose change during its history (and how)?