Home of the Fair Folk, Faerie goes by many names in many cultures. It has many portals to the material world, called trods, which take many forms - ancient monoliths, circles of mushrooms, strange caves with glowing fungi - and which can be used by the Fair Folk and those who follow them or are invited by them. Physically, it usually resembles the material plane on the other side of the closest trod, though everything seems to be on a grander scale and either more beautiful and more terrifying. The plane seems to evoke the youth of the world, when everything was grander and fresher and more imposing, and most visitors cannot avoid a strong feeling of nostalgia for times long past. Buildings created by the local Fair Folk likewise seem to be more impressive than their material world counterparts, though they are usually several centuries out of style.
Scholars suspect that the reason for this is that neither the Fair Folk nor Faerie itself can truly create something new. Instead they must ape other worlds and other planes, and likewise their customs reflect those they have observed on other worlds. Mortals who attract their attention should beware, for they are capricious and likely to involve them in games and intrigues that often have dangerous consequences without explaining them the rules.
Sometimes, communities with material plane equivalents have their own, unique name (which often resembles a more archaic name of its equivalent), but often the locals use exactly the same name for both locations. Scholars usually add the word "Luminous" to the locale name to distinguish from the "real" place (i.e., "Luminous Dartmouth"), although many people use the word "Bright" (i.e., "Bright Dartmouth") instead.
While it is said that Faerie mirrors the Material Plane, this is only part of the truth, for geography and distance have different meanings here. As a way of comparison, try to recall a lengthy journey you have undertaken. Unless your memory is perfect, you will likely not recall the entire journey at once, but a series of "highlights" you have visited or passed by.
In Faerie, those "highlights" are the whole of the journey. Each locale in Faerie seems to have a limited sense of awareness and a craving for recognition, so when the plane senses the intent of a traveler to reach a certain destination, the places who might be in his path compete with each other to be the way stations on his path. The "losers" in this competition just don't appear at all, and the whole journey is thus experienced as a series of scenes where one location blends seamlessly into the next, no matter how much distance and geography might be between them.
As each location craves recognition, travelers need to overcome some sort of challenge to proceed - a fight, a riddle, a physical obstacle, or some sort of interaction with the locals. Only when they overcome this challenge does the locale let them go, satisfied that they have recognized its presence and strengthening it in the process. If they fail or attempt to circumvent the challenge, they will be unable to move on, moving in circles and staying for very long times as the place feeds on their frustration. Skilled and canny travelers may be able to complete a journey that would take weeks in the material plane in a matter of days or hours. Unskilled travelers might take months or even years as they are trapped in the places before their destination.
Attempts to use this effect to move troops in warfare or otherwise rapidly transport large numbers of people tend to end in spectacular failure, as large groups tend to attract the more predatory locations. As always, these locations want to be memorable to those passing through them - and what could be more memorable than scores of "less important followers" dying in a variety of spectacular ways?
List of Faerie Locations
Adventure Ideas
Designer's Notes & Resources
The Urbis equivalent of the D&D 4E Feywild, though I decided on a more classical name for that realm. Its geography was loosely inspired by the Wyld of Exalted, as well as the realm of Fantastica in Michael Ende's The Neverending Story.
Note that many Faerie domains are interested in visitors playing through a "story" - but they often have a very alien understanding of what a "proper story" should be like. This gives you, the GM, the perfect excuse to recycle all those really horrible fantasy adventures you once bought and run them again - with the understanding that the bizarre encounters and equally nonsensical scenery were designed by an alien intelligence and that "meta" commentary by the visiting player characters would be entirely appropriate. As an example, I would recommend the classic D&D adventure "The Forest Oracle".