A portal in fiction is a magical or technological doorway that connects two distant locations.Portals are a common concept in sci-fi and fantasy fiction. They can be of two forms: either you must step through the frames of an object (a mirror, a cupboard, a picture frame, a gateway etc.) which serves as a portal or, when they stand alone, the portal will commonly appear in the form of a
vortex of
energy.
See more at Wikipedia.org...