The Invisible

The Invisible, (PROSE: The Shining Man) also known as the Sidhe realm (PROSE: Autumn Mist) or the "Lost Lands", (TV: Small Worlds) and referred to as the Marchenland by Jurgen Leitz, (PROSE: Autumn Mist) was the plane of reality where fairies originated.

It ran along a groove next to the plane of reality that humans occupied, on a different frequency to what they could perceive; (PROSE: The Shining Man) with the Sidhe being able to perceive eleven dimensions instead of just four, their realm, which could overlap with any given part of the Earth's surface, was generally "out of phase" with human perception, even though it was part of the same space-time continuum as the human "world", as opposed to being a parallel universe of its own. (PROSE: Autumn Mist)

When the Earth was young, the veil between the Invisible and the Visible was thinner, allowing fairies to cross the divide and wreak havok in the human dimension. (PROSE: The Shining Man)

The Ninth Doctor once travelled through the Invisible with Madame Vastra. (COMIC: The Lost Dimension)

The Fairies took their Chosen Ones there, including Jasmine Pierce. (TV: Small Worlds)