The Material Planes are the innumerable realms of existence within which are all the physical worlds of the Multiverse. Each plane may be thought of as its own universe, with laws, properties, and physical arrangements that can be similar to our own or wildly different.
The "Prime" Material Plane is home to the worlds of Eamon and Earth, their suns, their galaxy, and the rest of the universe observable from Eamon. Other worlds like Toril or Narnia are thought to occupy other planes, similar to Eamon's but distinct from it, though this is unproven and a matter of some debate among cosmologists.
Individual planes may be closer or farther apart from each other across higher dimensions, and while this is often difficult for material beings to envision, the result is simply that some planes are easier to reach than others. Interplanar rifts that naturally form on Eamon most often link to locations in adjacent or nearby planes, like the worlds of Diurla or Toril. Rifts to more distant planes occur less frequently. A sufficiently skilled practitioner of magic can theoretically open a rift to any material plane, but far-flung planes can be extremely difficult to find and reach, and all but the nearest remain mysterious.
Among the planes closest to Prime are the Diurlan, Zagoran, Amaranthine planes, home (respectively) to the parallel worlds of Diurla, Zagora, Imyn. The Plane of Eä, which contains the world of Arda, is also nearby.
