Manifest Zone

Manifest zones are locations that share a particularly close connection with one of the thirteen planes that orbits Eberron. Within a manifest zone, the area takes on properties of that plane; for instance, a manifest zone on The Frostfell is a link to the plane of Risia (the plane of ice) which makes the entire continent much colder than it otherwise should be. The effects of a manifest zone are related to a plane's proximity. For instance, the effects of a zone may wax as the plane approaches Eberron within the astral sea and wane as the plane grows more distant. However, even when a plane is at its most remote, a manifest zone still has powerful effects on the world of Eberron.
Manifest zones may be located in the air, in the ground, or even deep within Khyber. They are extremely long lasting, possibly permanent, although in rare cases a zone might disappear only to reappear elsewhere. Zones range in size and have been known to be as small as a city block although most are much larger. They often allow passage between one plane and the next; although for some zones this may be a one-way trip.
About ten thousand years ago, the Gatekeeper Druids developed a way to seal off a manifest zone during the Daelkyr War. They developed dimensional seals (or Gatekeeper Seals), which magically lock down the effects of a manifest zone. All of these seals, however, were designed to lock down manifest zones to Xoriat, and the magic to produce them was lost to the ages.
While once manifest zones for all thirteen planes existed, only twelve remain after the Cul'sir giants severed the plane of Dal Quor (the plane of dreams) from Eberron during the Age of Giants.