Earth 93 - Realms

Realms are extra-dimensional spaces created by beings of great power. When a Realm is created it is tied to a location and moment on Earth. That realm will only ever be accessible from that location, and its basic geography will always reflect the original moment of its inception, though it can become exaggerated over time and new buildings can be placed upon it. When traveling between realms one must always use the mortal world as a crossroads. Alternatively a realm may be tied to a single person or an object, but these realms are always much more limited and often the only person who can enter from outside is the creator. 
The smallest realms are the size of simple rooms. The largest created in living memory is the Faerieland which is estimated to be about the size of Alaska. 
There is a massive realm, the size of the entire Earth, called the Veil, or the Shade. The Realm is dark and misty, very hard to navigate. Wizards use the Shade to gather extra mass they need for transmutation, to draw souls needed for necromancy, and to store heat they draw away from another source. When souls die they enter the shade temporarily before eventually fading and theoretically ascending to the care of God. As a consequence, many death gods made realms within the Shade called Underworlds, which store souls in various afterlives and delay the process by which souls go to the true divine afterlives. 
The laws of physics may not apply in the various realms as well as they do on the mortal plane, causing time to pass at different rates in different realms, as well as giving the inhabitants of various realms power to say a big "screw you" to physics while inside their realms, if they so choose. This is part of the reason many of the older forces of the supernatural take rules of hospitality deadly serious--offending someone who can bend their reality around you is suicidally stupid.
Forming a (minor) Realm is one of the more commonly used forms of Learned Magic among experienced Wizards, to the point where experienced Wizards often create small realms to function as their base of operations or as a secret hideout. It is believed that mortals can even create minor realms while they dream, connected to them instead of a specific location. Realms require a certain amount of magical energy to create, and require more energy the larger the space is.
=== Major Realms ===
Realms the size of a city or larger are called major realms. To create a major realm, it often requires a large group working together to create the kind of Energy necessary to do it. Some Major realms include:
* Faerieland- A realm the approximate size of Alaska where the Summer and Winter Courts of the Fae are headquartered. Accessed from whats left of the ancient forests of Europe. 
* Avalon- an island realm the size of New York City. Home to one of the most well known wizards of all time: Merlin. Generally a save haven for Wizards of all ages, it is also the home to various magical artifacts, including the mystical sword Excalibur, The Philosopher's Stone, the Spear of Destiny, and the most powerful magical focus in existence--the Elder Staff among others. King Arthur still sleeps in the tallest tower of the citadel, waiting for the time when he is needed most. - Accessed from the British Coast. 
* Mount Olympus- the mythical home to the Greco-Roman Pantheon. Has morphed over the years into a sort of reality TV show set, where the petty feuding of these gods is played for maximum melodrama. Most supernaturals not directly involved try to ignore them, but the Pantheon is desperate for attention. - Accessed from the actual mountain in Greece.
** The Vineyard- a realm accessed from the Mount Olympus Realm and in the back rooms of most any disreputable tavern on earth, which is Dionysus' bar. Here is where gods and angels congregate to get drunk and have a somewhat mediocre meal. A parley is in place which mandates that no wars be fought here, although any number of good-natured tavern brawls can occur. Mortals beware, as the alcohol is stronger and the light-hearted brawling more intense than anything seen on earth. 
* Ljosalfheim - A Realm connected to the old forests of Europe. It is now the only surviving independent elvish kingdom. It has a loose alliance with the Seelie court and the government of the United Kingdom. It was made by Queen Danu, as a home for the elvish refugees of Álfheimr after it was destroyed during Unseelie allied Roman incursions into Germania. 
* Niðavellir- A Realm of tunnels and underground cities deep beneath the earth. It is said that the tunnels connect across the world, even beneath the Atlantic to America.
* The City of Shadows- a realm made by the Black Circle in cooperation with the Guild of Shadows to create a hideout for the dark forces. It is about the size of a small city. It's basically a city, only where all the architecture is Gothic-inspired and every road is a dark alley. - Accessed from a few secret entrances around the globe.
* The Plutonian Underworld- Hades's dominion. Being one of the more responsible of the Greek gods, Hades has no time for the foolishness of his brothers and sisters, spending his time instead meteing his own brand of justice towards the deceased in his dominion. The Plutonian Underworld is a Realm within the Realm of the Shade.
=== Major Wise Circle Realms ===
The Circle of the Wise maintains strongholds in small realms around the world. 
* Avalon: The largest and the capital of the Circle of the Wise. 
* Imperial Library of Constantinople: One of the largest and oldest Strongholds. It contains both Byzantine and Turkish sources and wizards. 
* University of Gondishapur: An important Iranian Stronghold. It contains the oldest records of the Persian Wizards.
* The House of Wisdom: Located in Baghdad. Built at the height of the Arabic golden age.
* Takshashila: An important Stronghold that changed hands between countless civilizations, from the Persians to the Gupta. It lies in modern day Pakistan. 
* Nalanda: One of the first universities in known history. Lies in modern day North-East India.
* Kānchipuram: Stronghold in South India.
* Biblioteca Marciana: Important Stronghold of Renaissance Venice. 
* Simatai: A Stronghold along the Great Wall where Wizards and Scholars hid during the Burning of Books and Burial of Scholars.
* Luoyang Taixue: A great Imperial library of Han China.
* Timgad: Library in Northern Algeria.
* Timbuktu Hidden Halls: One of the oldest Strongholds.
* Bibliothèque Sainte-Geneviève: A Parisian Stronghold. 
* Hidden Halls of Iona: A secret library in Scotland dating back to the 6th century.
* The Library of Congress: The largest Stronghold in North America.