Tutorials/Building a metropolis

You've built a house, have 20 stacks of wood and more cobblestone than you can count. So what do you do now? Why not build a metropolis?

A metropolis is a massive city, with lots of buildings. If you like, use Creative mode as that is much easier to do. If you want a challenge use survival, or risk losing everything and play on hardcore. Also, World Editors like MCEdit and WorldEdit can be very useful.

Here's how to set up a video-worthy city:
 * 1) You will need a relatively flat land to build on. Use Super flat, but you can only use this on Creative as there will be no ores to obtain. If you want to do this on Survival, use TNT to clear some space. Use seeds to get flatter land.
 * 2) Make a center building, a town hall that you can use to start your place off. If this is being made on an existing world, this can be your house. Be lavish and make it out of diamonds!
 * 3) Now you have 1 building. A start, but we need more! So grow your city outwards and make it bigger and bigger. Here is a list of buildings and ideas.

Note:
 * You should upload this to a server, as many ideas are intended for that purpose
 * This site can only help you but you will have to be creative on your own. Build what ever you like, that's what the game is about.

Introduction
We'd love to hear your ideas. A metropolis is a big city and a massive city needs lots of buildings and ideas to fill it. So please include any ideas you have, even absurd ones!

Note: Do not submit ideas that are already on this list.

THANK YOU SO MUCH!!! Your response has been incredible with lots of different ideas. Don't you dare be shy, we need as many ideas as possible!!!

City types
As well as having a huge city, You could make it have style. IDEAS:
 * Skyloft: A sky metropolis with floating islands separated.
 * Mountain-range: Name explains it all. Have it on top of a mountain.
 * Venice: Have your town submerged in water (or lava). Good for boats.
 * Stronghold: Make a city with walls and send lots of mobs to attack it.
 * Anvil: Have your city 150 blocks above the ground. Use glass for the street.
 * Cloud: Have your city 50 blocks above ground. Use snow or wool for the street.
 * Underwater: Use glass to make a dome and Put a town under it. Good for fishing.
 * Disastrous: Have volcanoes near and every so often pour some lava into your town. See how the towns people survive Lava and monsters.
 * SteamPunk: Make a flying city which is supported by giant fans, use lots of Iron Blocks and have factories with Cobwebs coming out chimneys for smoke.
 * Dwarf: Find a cavern or make one and build a city underground, use fence to hang glowstone from the roof for lights. Inside a mountain is a good place to put one.
 * High-Tech: Build lots of skyscrapers and create an exorbitantly complex redstone system (Big Brother alternative: make that redstone system track everyone's every move.)
 * Archipelago: Build your city on an island chain (You will probably need to build the islands yourself, so a world editor like MCEdit or WorldEdit is especially useful for this type of city.)
 * Treetop: Find a jungle biome. Build houses that wrap around the trunks of tall trees. Connect buildings with bridges made from wood and fences. Or, for a more modern feel, use minecarts and powered rails.
 * Twin cities: Have two cities next to each other. They could be deadly enemies, or a city where the rich live and one where the poor live. (WARNING unless you have plugins or mods that stop certain blocks in certain places from being destroyed both of your cities could go up in flames!)
 * Kingdom: Build a castle out of any type of stone. You can use wool to make stained glass windows (although you won't be able to see through them) or use regular glass panes. Then, around the castle, build the buildings you would find in a kingdom, like old moldy peasant houses, regal mansions for nobles and huts for their servants, taverns with dispensers so you can get drinks (milk buckets or water bottles), etc. Once you finish the houses, make a wall all the way around the kingdom with towers and such. If you are on creative, you can make NPCs live in the houses or and act as your humble servants.
 * Sky: Try building a community in the sky! Not only it looks cool, it also provides safety from hostiles to the residents of the metropolis!


 * Temple: Build a city as large as you can make it with one giant temple in the middle, medium sized temples around it making up the rest of the city and small peasant class houses (make them look insignificant) for the people to live in.


 * Mushroom Kingdom: Build a city on lots of brown mushrooms. Build it like Treetop.


 * The Necropolis: Build a large city with dark buildings and streets. (Best on super flat and creative for undead or normal inhabitants.) You can do it on a server.

divided by many areas. You can have some layers, sone "zones" restrictions and much more. Remember to have solid, hard pillars made with obsidian or iron blocks to sustain your maze of hallways protuberations. The pieces may be linked together by growing onto sides of roads. Here are examples of layers or "zones" :
 * Nether city: Have the city be in the nether and have lava everywhere. travel by mine carts. have buildings made out of Netherbrick. ( you can use the open space or dig out a big cavern for your city.) You can also have a little station in the OverWorld to give access to the city.
 * Crafty: Construct the buildings out of different-colored wool, fences surrounding them for protection due to wool's low blast resistance. Have the settlements placed to the side of stone brick streets, or have them perched on the sides of water passageways for boat travel. Optionally, add a city square where the most important buildings are located, having them designed in the most creative materials you can think of. (Wool blocks, iron, gold, diamond blocks, etc...)
 * Futuristic skyscraper all-in-one: Best for any biome, just need place for pillars . Preferred for creative. A massive, costing... and prehaps ugly structure. If you want your inhabitants to feel like being sheltered or compressed together, this is the best solution. Its designed as a heavy skyscraper with many districts and zone scattered trough it. You can build it of any form - Just remember to be futuristic and realistic. It can be a real maze with multiple layers and floating parts.. or a simple big prism with many corridors. Try to make it feel as if a nuclear disaster fell on the world and the ground-level towns are infected by zombies and that the toxic air obliterated the open-air districts. Your "roads" may be accesible by walking, and may be built with glass cover. They pass trough plazas like some kind of highroads. They give rapid access to certain parts of the skyscraper because it is

---Level 0 to 4 = Death zone. Sas to the outside. Everything, exept authorized military patrols with radiation suits, will be killed in case of being flagged as an infected entity. ---Levels 5 to 22 = Military zones. Access restricted for armed soldiers or highly authorized federal agents, scientists, test subjects or politicians. ---Levels 23 to 64 = Heavy Industrial zones. Big factories with high polluting. Laboratories. Sewers. Redstone power lines. ---Levels 65 to 80 = Poor zones. Low value housing. Low value pawn shops. High crime areas. Very populated zone. Army outposts. ---Levels 81 to 100 = Mid zones. Lots of basic apartments. Individual homes (3 peoples or more). etc. ...

Think about a futuristic city built in one huge building with floating parts, all these linked together.

Settlement Sizes
You don't have to have 1 big city. Instead you could have 10 small towns dotted about the place. Choose your ideal size.
 * Farm. This is just a few main buildings, with 1 purpose, to be a farm and farm crops and rear animals. To be honest, don't bother if you will create a settlement this small.
 * Hamlet. Maybe 4 or 5 houses and a small shop? This is the next step up from a farm, and where EVERY settlement will start from. Carry on building though...
 * Village. This is the entry-line settlement where you can leave it. There should be 7-10 buildings with shops, churches and pubs. Think of the size of NPC villages.
 * Small town. The next step up from a village, this might have a train station (maybe leading to the country), numerous services and should be quite big by now.
 * Town. This will have a factory, a gift shop, and maybe even a night club. There should be paths and every type of service.
 * City. Skyscrapers, narrow streets, subway, stadium, this is a central hub for everything. Modern materials should be the main key idea here.
 * Conurbation/metropolis. A conurbation is where a city grows so big, it merges with another one. In Minecraft this can be a REALLY big city. A metropolis is also a big city. It should be easy to build one of these with the ideas on this page.
 * Country. This isn't necessary, but it is ideal. Countries may have lots of trees, tall grass, houses, and overall, mountains. If you are on Superflat mode, it might be a bit tricky. But if you are looking for a challenge, go for it. Anyway, continue building...

Interior design
A city with no furniture would look incomplete. So here is a list of ideas to fill them! Feel free to make additions to the list, as long as you:
 * 1) Do not post an idea which is already here
 * 2) Please include a small description to introduce your idea. Thank you!


 * Chairs and tables: Take inspiration from NPC villages by using stairs, fences and pressure plates, or design your own!
 * Books: Bookcases can take a bland room and give it a more lived-in feel.
 * Fireplace: If you want to have a cozy-looking feel, why not build a fireplace? Make sure that if you've got a wooden house, you might want to place some stone or some bricks into it. If you've not sure how to build one, think how a fireplace might look if you were at a house. If you want to have your fire burning forever, use Netherrack!
 * Paintings: Everywhere, paintings look nice. Stick some up and keep destroying them until you get the perfect one.

[Furniture Tutorial]

Streetlamps
Mobs. Don't have them in your city. Not only will streetlights prevent these from spawning, but they will give your settlement a cozy feel and look good too. There are many designs out there, but a good one is two fence posts on top of each other. Then place a wood block on top and a torch on top of that. Finally, place 4 trapdoors on the wood block on all 4 sides. Place as many as you can.An alternative is to put Glowstone on your pavement. If you want to make your streetlamps technological, make a power line system with Redstone Lamps. Make a building near the middle of the city, and make levers inside. Connect those levers to the power lines. Flip the switch, and the city lights up before your eyes. Floor lighting looks best with Glowstone and stone bricks but is hard to get large quantities of both. The final one is 5 fences stacked on top of each other. Place Glowstone on the side of the forth fence post from the ground. The Glowstone should be on the side(s) which you want the light to be on. Place one final fence on top of the Glowstone. Looks like a regular streetlamp, except it never turns off.

Paving
Grass doesn't do justice. Though time-consuming, paving your streets will improve the feel of your city drastically. Stick with a simple material like Cobblestone, Wooden Planks, or Stone. Mossy Cobblestone is good as well, but hard to find on Survival. Just like NPC villages, Gravel is a good choice too. Using water can allow boats for transportation.

Transport System
As your village turns into a town, then a city, you might think about putting in a minecart system to shuttle players around your place. See Tutorials/Train Station for more information about minecarts, or see Tutorials/Transportation for more information about other types if transport. You can charge people items like gold or diamond. It can be underground or overground.

Skyscraper
Your city can be impressive, so brag and build a tall building so that people can fully appreciate the vastness of your creation. Make it as high as possible. Good luck with that with the new max height.

Nether access
Build a portal and let people get to the Nether. Even better, if it spawns you right next to a Nether fortress, then you can make a tour and block off dead ends. Or just make a netherrack mine. Build a nice nether-style building around the portal so people can easily see where it is.

Public Mine
Why not? Build ladders down to Layer 12 and let people have easy access to ores. They can extend it and you can signpost some caves and ravines. Destroy spawners in Dungeons and operate a first come, first served policy. Remember, you cannot make any mines if you play on super-flat

a good way to mine is to branch mine. its very efficient, safe and gets you a lot of bling!

HOW TO START A BRANCH MINE:

1. Dig a 3x3 staircase (NOT going Straight down).

2. Figure out what level you want to miners to dig at.

3. Dig A 3x3 tunnel connected to the end of your staircase, It can be off any side(s).

4. Dig 1x2 tunnels in your 3x3 tunnel for your miners to use. (Optional: Pre-mine some tunnels)

5. Continue your 3x3 tunnel for as long as you wish and add as many 1x2 tunnels as you wish.

6. Enjoy! :)

Forest
Fence off an area and grow trees in it. Have a chest of axes and a chest of saplings nearby and people can get wood, since you will have cleared trees out. Even better, corner a forest off to save you another job. Two birds, one stone.

Farm
It's a fact: you need a farm. Have an area for growing crops and rearing animals. Also, charge people for them and have a farm shop. Have a stream/ river going past farm so a watermill can be built, if not build a windmill, or better still both.

Slaughterhouse
How cruel...next to the farm will work well. Simply make a building and put a mob grinder in it. Have a small shop at the front and redstone(for blood)in bits around the place.

Help Building
Be nice to newcomers. Have a house full of crafting tables and furnaces. Even better, put some wood in a chest. They will thank you in the long run.

Building Plots
For server use only and a great space-waster. Fence off some areas and let people start a life there. It can be good to come back and see what has been created.

Houses
So obvious. Make some giant red Mushrooms and put a ladder on the white bit, the stalk. Climb up and make a floor. Place a bed, a crafting table and a furnace inside. Make more and charge people rent to live in them. Great fun!

One good way to build a house is a log cabin or a modern house. You can build it with a brick stone floor and a nether brick stone blocks as supports.

You can also use some furniture.

Making chairs with stair blocks and signs is a good way to make seating.

To make a good kitchen you can put signs and pressure plates on furnaces. You can also put a Caldron and put a open fence gate on top to make it look like a sink! put 2 iron blocks and and a button and you got a fridge! Make fences at each end of the counter and put some book shelf blocks and put on open trap doors and it will make a neat cabinet. Put some powered pistons and put chairs to make a family table.

To make some good plants for your house just place a grass and put a rose or some other plant and put signs around it.

If you want to make a good audio system put fences with black wool surrounded by signs that look like radios.

To make good furniture for your bedroom hear are some good ideas:

Put some stairs and slabs in a fashion that makes them look like a dresser. then,put some trapdoors on the side and front.

Another awesome way to build a bed is to put supports made of sand stone or fences surrounding the bed and then putting a red wool tent on top.

Another way is the same way as the dresser but with beds on both ends.

If you want to make a fish tank you can put 2 book shelves and then 2 ice blocks on top and put trap doors around.

Cool office ideas:

Put desk made of powered pistons or wool and then put a pressure plate and a small panting and put a lever and some chairs next to the desk.

Enjoy ;)

Spleef

 * See Spleef for information on the game.

You can make a massive stadium which will make your city impressive. Enjoy! Set up a gambling system, 1 wood in 3 wood out? 1 or 2 small food stalls would be good for the spectators. A snow block floor is the best, because an iron shovel an practically destroy one with a click. If you have a floor of lava below, make sure to keep it well away, because the lava will melt the snow. But then again, that would be more interesting...

Olympic games
Have competition with giant stadiums and tons of competitors. Although don't let everyone compete. This is recommended for servers. Have a swimming competition, a minecart race, a cliff jumping challenge, bowling, item throwing, archery, and skating, etc. Hit the losers and award the winner. Charge people to see the events. Have a trophy, this could be a excellent griefer trap. Have an Olympic Torch, hooked up to redstone and netherrack and set it on fire to start the competition! Unite cities for these games and have festivals afterwards. Go nuts! On a multiplayer server, you can even charge users to bet on the winner!

Shops
Make shops and place chests with all the essentials in them. You can charge people for what they have and make some money. Pretty much needed. Also it could be a good idea to make them all in one building, and make a shopping centre!
 * Potions shop – A place where you can buy all kinds of potions.
 * Enchantments shop - A place where you pay someone to enchant your tools/weapons/armor.
 * Food market – A place where you can buy any kind of food.
 * Local shop – Sells everything but junk food (cake or cookies). May also sell tools and armor but probably nothing past iron. (may also have a higher price).
 * Supermarket – should have most things like tools, armor, and weapons of all types of material, all food, and maybe some potions. This shop could be one big building with lots of different shops in it or one big shop.
 * Clothes shop – This shop only sells armor in it.
 * Pet Shop- This store sells wolves and ocelots. Sold Untamed. Tame after purchase.
 * Garden shop – this shop will sell flowers, saplings, bone meal, water buckets, dirt/grass blocks, sand, cactus, nether wart, seeds (all), melon, pumpkin, red and brown mushrooms, lily pad, vines, sugarcane etc.
 * Exotic shop – This shop sells items that are a little more difficult to find such like glowstone, lapis lazuli, blaze rods, ender pearls, gold nuggets, apples, golden apples and eyes of ender.
 * Forge – Charge people to craft a tool or smelt a block.
 * Building shop – This shop sells common and exotic building materials such as stone, cobblestone, brick blocks, glass, glass panes, netherbrick blocks, obsidian, wood, wood planks and bookshelves.
 * Redstone outlet - A shop which sells all things redstony. Have some examples of redstone going underground like a piston lift, a piston clock or an automatic farm/cobblestone generator.
 * Pharmacy - A shop with potions (but only good ones) and all foods except cake. (C'mon, have you ever seen a cake in a pharmacy/store?)
 * Scrap Shop - Where players trade in beaten armor, damaged tools and blocks they have no use for, then the owner sells them to people who can't afford full grade armor.

Theme park
You can also make some fun attractions as roller coasters, haunted houses, a maze or some others, just think! :) You can even make one in the nether, but protect it from ghasts and lava!

Museum
You can build a museum to display informative content and have various exhibits. Here are three ideas to get a museum started: An ore room, which displays the eight types of ore, and/or a mob room, which uses mob spawners or spawn eggs. You can put a room full of paintings and put some funny names below them. Or you could make some statues or "fossils" and put them on display.

Bank
A good idea is a bank. A bank can be a building with lots chests in a secret vault that only the owner and the bank owner (preferably someone who is trustworthy) can open. Each player can have a different vault. Also there will be a reception that can exchange currency (eg. 50 coal for 1 iron)

Zoo
As we have said above, in the museum, you can make a place with all the animals and mobs that are in the game(snow golems, chickens, cows, mooshrooms, pigs, sheep, squids, endermen, wolves, zombies, zombie pigmen, blazes, creepers, ghasts, magma cubes, silverfish, skeletons, slimes, spiders, cave spiders, zombies, ocelots, cats...). If you are really ambitious, you can even try to have Spider Jockeys and charged creepers. remember to do the room of each hostile mobs full of glass

Airport
Even though ornamental (unless with use of a mod), an airport would look very cool. You could even make planes out of wool. In your airport you will need: a check in-lounge, a departure lounge, a watchtower, a runway, a shop, a car park, and a few planes. You could use iron doors and note blocks to recreate the doors.

Space Center
You could even build a rocket ship (out of snow blocks, wool, or iron blocks) ready to launch with minecarts w/chests. You can also build a large TNT cannon to launch players or animals into "space." Build a floating Space Station 150 blocks high and add solar panels, rockets and escape pods. Add Lasers (Lava Falling) and cannons (TNT) if you want. Add other space stuff if you want as well.

Castle
If you have made a metropolis, why not be mayor or even king? Make yourself an obsidian fortress, a floating dream palace, a flashing lag generator of a tower made of redstone lamps and randomizers, or a simple medieval castle. Build on a mountain, or in the center of town. Just make sure it's cool.

Maze
For fun you could build a giant maze, or a labyrinth filled with zombies and skeletons. Make it as dark as possible with traps and pits. Or a lovely pink one with plenty light. Maybe a hedge maze is of your taste. Possibly a neat, complex forest maze will satisfy your hunger for something to do. Or you can be cruel to your test subjects and use pistons and timed randomizers to make an ever-changing puzzle.

Bridge
Just a path over pits and rivers for players. You can also put up toll booths to charge people for going over a big river or lake.

Landmark
Make something that people know it is your town. It should be something impressive, maybe a model of the deathstar or your skin? Maybe something else, works well on servers if you want the people to know and remember your server.

Church
Build a big building for a cathedral or a smaller one for a normal church, you can make it look like a real one. Just remember to be respectful. If you want, you can copy Vareide's 'Bacon temple'.

Redstone constructions
Build weird mechanisms with redstone in your buildings or make areas full of them that makes your city look more advanced. Such as wiring all the buildings so they have electric lighting. Or make a clock tower, or track your resident's movements, or have streetlamps that turn on at night.

Suicide Booth
Cruel, I know. A favorite to bored players and cheaper way to make a slaughter machine! You need: Steps: If you want, add multiple paths in the chamber for different ways to die!
 * A Wooden Door
 * An Iron Door
 * Lava or Cacti
 * A Switch
 * A Sign
 * 1) Build a booth 3x2 high.
 * 2) Make a window for a person to operate the booth.
 * 3) Dig a 5 block deep 2x1 hole.
 * 4) Place the iron door.
 * 5) Wire it to the switch.
 * 6) Open the door. Place the cactus or pour the lava.
 * 7) Place the sign above the window saying "Thank you for using the Suicide Booth!"
 * 8) Enjoy.

Gameroom
Surviving and building is fun, but so are games. Make a game room with games. Server required. Some examples are: Room 1: 5 Zombies Room 2: 5 Skelaton Room 3: 2 Wolves Untamed Room 4: 1 Creeper Room 5: Mini-Boss: Enderman Room 6: Resources and Portal Nether Room 1: Boss: Ghast Nether Room 2: 5Zombie Pigmen Nether Room 3: 1 Large Magma Cube Nether Room 4: 3 Blazes Nether Room 5: Portal Back Home During a game, no-one else can play. At the end of each game, the owner of the game switches to craetive mode and rebuilds the dungeon. Learn More at the Zelda wiki.
 * Target Time!' A game where a bow is used to shoot a wool target.
 * Pork Pusher!: A game that includes a big, black, hollow box with a glass pane screen representing a TV. The inside is decorated colorfully. Outside, by the screen, are 3 levers representing joysticks on video game controllers. The levers operate 3 pistons, inside the TV. The player attempts to push a pig around as many times as they can. If the player makes 20 successful pushes, they push a button that drops a cooked pork chop on them. If the player fails, they push a button that opens a pit below them, leading to their death.
 * Wolf-run!: A game where there are wolves. Hit and run and see who can survive the longest. 2+ players.
 * Graveyard: A Graveyard with Spawner's under graves.Hide chests with armor and weapons. 4+ Players.
 * Pig Hunt: Build an arena with pig spawners in the middle and a colored pit at the corners. Players get One wheat and abduct pigs. Can be done with zombies for DEATH!
 * Spleef: Mentioned above.
 * Drop Party: Players are put in a room while the admin drops items like pistons and sugar and lava and nether portal blocks (Random stuff) these can be taken home later.
 * Take Em All On!: A game that a player goes into a dungeon filled with traps, bunkers to sleep in, hostile mobs and an Nether Portal. Go into the Nether and wander around to find the end of the dungeon, a bunker containing a prize and a portal back to the overworld. 1+ Players. Inspired by Take Em All on in Legend Of Zelda: Spirit Tracks. An Example of a dungeon is:
 * Paintball: Players are put in an arena. They are given bows and arrows then fight but remember winner takes all. They are multiple variations like Cap the Block, Domination, President and Regular.
 * President: A member of both teams is given a leather cap (the "president"), then first team to kill the others "president" wins.
 * Cap the Block: A game where a dirt block is placed in the arena then players have to retrieve the block and place it in their base.
 * Domination: Same as Cap the Block but there are multiple blocks in the arena. The first team to get the most wins.

Cinema
A simple picture house. Can have actors or pistons and redstone moving things about. Whether comedy or romance, they still have to pay. Have a food bar selling "popcorn" and "cola".

Admin Island
If uploading to a server have a place where no-one can get to (except your friends). It could be a cloud, a real island, an impossibly steep mountain, Skyscraper with everything at the top, underwater or hidden underground. You could even have a Private "Jet".

School
Have a school showing people how to build things. Show them useful tools for the job. They and their single player world will thank you.

You can even make a redstone school to teach people how to use redstone and create huge redstone mechanics!

Resource Building
Make a big building which houses many resources and blocks for your residents. Make an infinite water source or a cobblestone generator. Have furnace rooms for people who just got out of the mine and have many stacks of iron or gold ore to convert. Make a HUGE storage network and charge people to store their extra stacks of dirt or cobblestone!

Harbor
A port will be useful if your town is spread across several islands. Craft boats and build ships.

Music Disk factory
Use the method in the guide Tutorials/Music Disc Farming to build a factory. Set up a shop and charge people loads for them! If you are an Op in your own server, then change yourself to Creative and then put lots of disks in a chest.

Celebrations
Why not? It's your city! Create a special day of some sort and invite all your town residents for a huge festival. Decorate your streets with colorful decorations and serve cake, cookies, and other food and show your people your festive spirit!

Power station
This is pretty much a building with redstone that can turn things like: Lights, pistons and doors. Have it connected to houses and charge people(Only useful on servers where redstone is scarce- as normally you could just place a redstone torch for all the power you need).

Cake Factory
Hire players to work in a factory where cakes are made. Make a lot of rooms with the cake recipes and a crafting table, and a chest minecart, where loaded onto to deliver to shops. Placed near the bakery would be good. Could be sold at a bulk discount price.

Cemetery
Want a place to remember the dead? Make a 10x10 square. use fence and a gate. the tombstones can be out of any block, preferred stone. place signs on the stone with a persons name and saying on them. also add a wooden cross to add some more feeling for this. Caution: put some light in the cemetery or else zombies will come. But then again, that would be kinda cool...

Embassy
Make other peoples' voices heard! Build offices that represents another server, a nearby city, or even mobs like testificates, creepers (build walls out of obsidian or they will blow up the rest of your city), or ender-creatures! Also remember to build them next to your city hall.

Police Station
No griefer goes cleanskin, so build a office for ops or even the in-game cop. Also include cross-hearing rooms, passport offices and even a jail next to it.

Jail
If your behavior isn't good... you will go to the jail! You can make them out of cobblestone/obsidian, put an iron door with a lever on the outside and a windows of iron bars. If you are in creative or you are a admin on SMP, you can make them of bedrock. Make sure they can't break out by breaking blocks! Make sure to take any items from them. (Don't have to with bedrock in survival) You can break obsidian without a pickaxe, just takes long time, so you this method isn't practical. You may also have armed guards patrolling the area.

Obsidian-lava-obsidian. Put a wall of obsidian then lava, the another wall of obsidian. This way, if a prisoner tries to break the inside wall of obsidian, they get punished by lava in their face.

In 12w22a, the new minecraft snapshot, "adventure mode" was added, making it so the player on said mode cannot break blocks. This can be very useful if creating a jail that works and looks like on too. Be careful of players doing /kill to respawn!(Maybe say if they do the get banned). (Also possibly use glass to infuriate them, just a thought easiest block to destroy is unbreakable.)

Hospital
Some players had a bad night, so they need some refreshing. Make a BIG house with a red cross on it, and fill it with beds, healing potions, surgery rooms, and that kind of thing. Hire "doctors" and get them to wear nurse and surgeon skins. You can even sleep in one of the beds there, and you will wake up there after a bad episode!

Fire Station
Griefing protection is first and last, but your wood constructions need a plan B. Fill a house with water buckets, armor enchanted to fire protection, and minecarts ready to move out in maximum speed. Block 51 must die!

As an extra measure, you could have a button in all of the houses to call the fire station, connected with redstone. In the fire station you could have a wall of redstone torches, corresponding to the towns buildings, so when someone presses a fire button, the corresponding torch would light up. Just an idea.

Ghostbusters
Some blokes dedicated to killin' zombies n' skelies! Get together some people in cool skins, with enchanted bows, minecarts and cue the music!

Puzzle House
A series of rooms that require the user to use logic in order to move on to the next room such as a hidden door behind a painting or a code written on signs needed to find the correct sequence of levers to pull. Leave it for someone to figure out. (or) Charge people admission and add a time limit. Whoever doesn't get out by the end must forfeit an item from their inventory selected by the ticket master and whoever gets out before the clock stops gets a handsome prize. (Note: Make sure to add a protected chest for the solver as the use of anything in their inventory during the trial could be cheating. Also do not allow the destruction or placing of blocks, immediate disqualification should come as a result.)

Bookstore
A Building dedicated to books. you could have all types of books including guides or even Mincraft fiction. you could have a group that writes the books sells them to the books store (or give them) and then the bookstore can sell them. Note: This can only work with 12w17a Pre-Release or you can wait until Minecraft 1.3 comes out if you don't want to use Pre-Releases

Casino
A large, flashy building in which to spend the day's hard diggings. Buy some chips (represented by ingots or dyes) and hit the tables or the slots. Cards can be played by using certain items as cards (Redstone Dust = Red Diamonds; Black Wool = Black Spades), and their amounts as values (Ace, Queen, Jack, King, & Joker are assigned to their number amounts). Just be careful not to lose it all...

Lottery building
Build a medium sized building.You can pay in Iron Ingots,or even Diamonds as money.Build a dispenser with a button.Put any prize you want in the dispenser(Armour,diamonds,weapons,tools,and all other stuff).A lottery building is really useful on a server.A simple way to get rich!

Restaurant
Why not? Build a place with food and drinks... for a price. Sell water and milk for drinks and all kinds of foods for... well, food. You should be able to order meals. Build blocks above the front counter with signs on them saying the food and drink you can buy and the price. Put wooden stairs for chairs on either side of a fencepost with a pressure plate on top (for a table). A piston with a redstone torch under it is another table. There should be chests behind the counter, you can hire people to work at the restaurant behind the counter, or admins on creative could run it. Make sure to fill the chest with food and buckets of water or milk. Just in case the food runs out, there should be a room behind the counter for the kitchen with even more chests of raw food and ingredients and an infinite source of water, with a bunch of furnaces and coal to cook the food, and some crafting tables for cake and cookies and bread and such, then when food is cooked it is transferred to the chests behind the counter, there should be no regular chests, just large chests. Is you are really ambitious, you could automate everything there. Minecart chests to send food to the counter, and automatic farm where it all comes to a single collection point. The possibilities are endless!

Condos
If you need a major amount of housing in a small space, why not build a condo? It'll add character! Have condos, a shop, maybe a pool or club. Be imaginative!

War
Minecraft has never been peaceful and never will. If you can't beat it, join it. Build forts, bunkers and wage war against castles full of traps, monsters(creepers are not recommended), other player, and challenges. Build TNT cannons and build an army. Award loyal soldiers with positions like the general. And you thought Minecraft was bloody before. Oh well, Fire!

Defense
Make sure you have walls around your metropolis. Put cacti on top of the wall to keep spiders out. You can also add archer towers if you want. Just make a 3x3 square on the wall with ladders to get up to them. Add moats with lava for death of your enemies. Just be creative!

Dance party
Let's party! Have a redstone lamp blinking and obsidian with buttons on them(disco ball and speakers). Wire these up to a DJ station. Have a dance game where it displays a color and you jump on the wool of that color. Have poison for drinking(note to self, don't drink to much). Invite everybody and Listen to sweet music going.Let's party!

Apartments
A lot of houses in one building. In my sister's metropolis, she put 7 floors, 4 rooms on each floor (equaling 28 rooms in total). Each floor should be built out of a different material (e.g. stone, gold, sandstone, lapis lazuli, redstone ore, obsidian, diamond) with different prices for each floor. Make sure to put a lobby on bottom. Each room should have two large chests, a bed, lighting, a crafting table, and a furnace. You can add more or take less if you want!

Temple
Though it may seem similar to a church, it isn't the same thing. You can make a humungous temple, or a little tiny shrine the size of a sandstone well. You can have an area for training in magic (if appropriate), a way to sacrifice, table, lava, bottomless pit, ect. And make sure the temple makes sense; for instance, put a god of shadows underground,and a god of time and space with things such as end stone and other mysteries things.

TV Studio
Pointless but it gives people something to do such as filming soap operas or winning gold and diamond on a game show. Hire directors, producers, actors and actresses, build TV show sets, have pretend ratings etc.

Garden
Make a massive garden(100x100) in the middle of your city. Take inspiration from New Yorks Central park. Use bonemeal to grow trees and flowers everywhere, have paths made from gravel, and spawn friendly mobs inside. Surround the premise with iron bars. Make sure to keep well light with the use of streetlamps to avoid monsters spawning. If you feel creative, constructed a lookout tower with a spiraling staircase up to the top, which has a view of the whole city. You could also add attractions such as caves filled with ores and charge people for a guided tour. be creative with it.

Training area
Make a massive training area that teaches the player every single trick in the book of Minecraft. From splash potion jumping, to sniping with the bow and arrow. If you think that the player is experienced enough, then it is possible you can recruit them for a guard.

Weapon Shop
This shop sells Bows And Swords.( including Enchanted weapons. ) Sell them at your own risks.

Weapon license
This building give people license to have weapons including bows and swords,the price of the license is 20 Gems(With the 1.3 update you can use emeralds as currency).The expiration of the license is 50 days.

Villager Shop
If you don't have a server or people on your server don't like to trade have a villager trading shop! You can use spawn eggs or just lead villagers there.

Stadium
Build a massive area for a multitude of events to be held. This could include by not limited to: Spleef, Sporting events, Battles, Survival games, Parties, Weddings, ect. This should be built to be able to change the field for the players, For example, You can change the playing field from Grass to Glass for spleef games, and that glass back into Stone/dirt for Battles/fights to death. You could hold sporting events like Track and field. Maybe even hold Olympic Games.

Pawn Shop
build a regular sized building with a player running it where you can sell your items or get the player to hold on to your items for iron or gold ingots.

Wizards shop
Make a medium sized building with a small desk area. You can hire someone you trust to run the place. Behind the counter, you can put a brewing stand, and a lever for a piston door to the enchanting room.