Random Idea: several diverse major cities from all across Earth disappear and rematerialize just outside Equestria as islands or large levitating chunks of rock, and are forced to become city states in the new world.

That'd be a great series but a terrible story unless you're very good. It would be a nightmare to follow converging plotlines from several different groups of characters from several different locations. Have a set of stories all focused around the 1st-90th contact for each individual city and calling that a series and doing the same for another city would be great, though.

I could see that as a sort of reverse Conversion Bureau, minus the conversion part.

3998071 Were I to write it into actual story, I'd probably choose a single city as an anchor point for the plot, with other major cities being only mentioned, briefly visited, or have prominent figures from them appear during heavy diplomatic stuff.

3998058

3998097 Hmm, I'm starting to get some rough plot ideas percolating in my mind. I have had an unusual obsession with Seattle for the past several years.

1632 by Erik Flint comes to mind as an example of how to do this right. (whole book available at link)

This is a small mining town in the USA transported to Germany in the middle of the hundred years war.

There are a couple of notable Pony attempts at something starting off similar - Ponyville USA - where it's ponies on earth, and Island in the sea of Equus where it's the whole USA off the sea.

You need to carefully think about power imbalances.
Even small cities are likely to bring along police departments, army bases, airports and other similar extreme combat abilities.
Unless you're going to _greatly_ expand canon Equestria - it's questionable how they can cope with even a 'small' city.
With the best will in the world - you can't expand food production or other services significantly without hazard.
Dropping New York onto an Equestria with half a million ponies is going to lead to only terrible things as almost every single one of them tries to 'bug out' in the face of no food or prospect of food and collapsing services.
Think every bad zombie fic you've ever seen, but the Humans wanting to roast ponies for food.
(or a substantial fraction thereof).

To have a story with some long-term narrative you pretty much need a reasonable number of humans dropped into an Equestria that can materially support them as 'refugees' until they can get their own supply networks up and running.

It might almost be worth setting this 20 or 50 years down the line - where it's the second generation after - say Baltimore - got swapped with Baltimare.

A straight out swap mitigates the supply issues - as (to a degree) 600K people can probably survive on what 600K ponies did.
I would suggest a smaller town that has no hope of self-sufficiency in many things.
As well as a tractable size population - several thousand, not hundreds.
This has the advantage that you can sanely portray the leaders - for example if you pick a large city like Baltimore - you're going to have several layers of governance, police, ...
You're pretty much going to need to do it properly to write a political procedural novel.
Versus being able to take (as you might find in a town of several thousand) the local sherriff, and some prominent figures.

http://1632.org/1632tech/deadhorse.html - is an excellent page to start you thinking.
This is a list of people and resources, and issues maintaining a 'modern' civilisation with a very primitive resource base.
How, for example - do you make stainless steel?

This is a page for collaborative

3998128 I'm actually familiar with that novel, quite a great work of alternative history if I say so myself.

3998116
Well, that's a really good city. Some suggestions I have are San Diego, Jersey City, and even Manchester and Warsaw if you consider non US cities.

3998058 look up the game warriors orochi.... same premises.

3998211 Philidelphia should appear in Tartarus.

3998058 Cool idea! Roll with it.

You may want to consider just how this concept can be applied pragmatically. Here are a few points to consider when executing the idea...

1) Which time period do the cities come from? This is for taking technology, population and area covered by each city into account.
2) Do you want all cities to be transported at once? This could have a major impact on both human and Equestrian society.
3) Will they have miraculous amenities? This is primarily for modern cities in that the impact of losing their electricity and water supplies would be...
4) Should there be a language barrier? Plot advancement is most likely to be affected by this one way or another.
5) Is the world of Equestria spherical or planar? This would affect the socio-political decisions of the Princesses when so much land is suddenly occupied.

3998780 'Spherical or Planar'.
The taste of Grass. - murder by bureaucrat.

An alternative used in this story - whole earth population into a tiny non-euclidian Equestria - 'The Exponential Lands' - in order to allow for _vast_ population expansion in the future, ponified humans are dropped with adequate supplies in an Equestria where the edges have been stretched out for millions of miles.

sounds like a nightmare to write but I would read it

3998152

One big thing to consider is where do the Cities get their power supply from:

If there is not a plant within the City then they just lost all electrcity. Also cities tend to have higher crime rates than countryside, result of having people concentrated. What happens when they flee the city to aviod Police etc. Prisons for that matter, if there aren't in the city what happens.

Utilities as a whole are something to consider seriously.

Food Supply, how much food does a moderately sized city like oh say Charolette, or Raliegh NC require per day. Are we talking just the city limits of the whole metroplitain area around them.

This is an awesome concept, that would take some serious research and excellent writing. Still I would love to see you go for it and would very much enjoy reading it.

3999052 What I envision, is entire metropolitan areas appearing as self-sufficient, and semi-sufficient islands or floating islands as seen on Pandora in the movie Avatar. One of the driving points of such a story would entail the cities trading and/or coming into conflict with Equestria, one another, and other nations on Equis.

3999060 Interesting concept, particularly the floating Island bit. I really do love this concept and right now my brain is running wild with it. Given that you area taking the greater areas around these cities raises some interesting questions. Before you get into them I want to offer to volunteer to help you with this if you need any, this is such a awesome idea jibes well with the kinds of things I like to imagine, read, watch, etc.

1) If they do bring their power stations fueling them will become a issue pretty quickly. cities that already have green power generation have a leg up here, and anyone that can build wind turbine is going to have a good edge since a floating city have plenty of surface area for it and should get plenty of wind

2) Water, water is going over the side but probably not getting recycled into the city. Are they going to have to import it or be nature of the magic that causes them to float it recycles into the island as ground water, or are they reliant on Rainwater? This then raises the question of weather for the City states, do they retain local Earth Weather or get Equestria weather.

3) Food to feed that many people just isn't being grown in that kind of space. Now responses to this issue would be an very interesting item.
Do people being growing gardens, turning run down highrises into vertical greenhouse that use aero- and hydro-ponics. Would people me able to get any kind of meat into their diets. Fish and muscles imported then when possible raised locally would be interesting but it would quickly become a luxury item.

4) Money: what would the city states do for money. Keep their national currency and print it on their own, abopt a human currency good in all city states or go to the bit.

5) would any of the citystates have the experts and potential industrial base to build rockets and begin launching satelittes for communication to other citystates. For that matter would they want to connect to one another via cables, depending on distance, to reform the interent as best they could based on what servers remained. City Selection here has a major effect. If you took silicon valley for example it would be very different from takeing Boston of Atlanta, or Tokyo.

6) Settlement and Population growth: Since these Citystates by human nature will seek to expand how will they settle? Will cities grow up beneath the floating cities acting as resource and food generators for the metropolitan areas? Does a class system arise from this? How does that happen.

7) Reactions of Native: does anyone have myths of humans as their boogey-men, prehaps Dragons or Minotaurs fear man since our legends usually involve having killed them. Could also be a pegasus legend since a man wipe out all but one in Greek Mythology.

8) Human Science coming at odds with local magic, the effects of magic on humans, the nature of Equestrian Magic. You will have to decide this from the get go because it will set a tone for the story.

9) Human consumption vs Equestrian Conservatoin: Based on what has been seen so far Equestria is a fairly conservative live in harmony with nature by making it completely reliant on us for basic things to happen kind of society. How will that handle human styles of mountain top destruction, clearcutting, even with replanting, and other things we do to get the resources we need. Would love to read Twilight Sparkles Reaction to reading Upton Sinclairs The Jungle.

3998058 Would be fascinating if some of the cities allied themselves with other places. Some end up in equestria, others end up in the Griffon empires and become client states or such. The possibilities! They are limitless.

This kind of reminds me of the Elfhome series by Wen Spencer (first book read for free from the publisher here: http://www.baen.com/chapters/W200311/0743471652.htm)

In that series humanity built a portal in space but due to resonance or whateves, there was another, second portal on Earth, that basically zaps Pittsburgh to the Elven planet for 30 days. (slightly more complicated than that, but that is the gist of it)

That actually is a really fun series and I really like the idea of humanity doing something completely unrelated to finding alternate dimensions and then accidentally finding them in a huge way.

Maybe some pony or other sorcerers could be experimenting with stable teleportation gates or some such and they accidentally trigger a cascade failure that swaps a huge chunk of the Equestrian city with the equivalent Earth city.

An idea for this is that you could make this somewhat sci-fi and instead use arcolgies, which are basically self sustaining cities condensed into a singular hyper-structure.

Berlin in waw. lulz

I would die from excitement