- You may be looking for the Eremites' Labyrinths or the concept of a labyrinth.
There existed a mysterious network of caves existing outside "normal space", which had "terminals" in the depths of various normal caves in different places and times all over the universe. It was colloquially called the labyrinth by those who journeyed through it; its proper name, if it had any, was unknown.
Nature
The labyrinth often shifted, making its exploration extremely difficult. In addition, gravity inside the labyrinth was unstable, and it was haunted by a mysterious being called Mister Cold. However, there existed one accurate map of the labyrinth, known as the Yauhtepec Map.
The planets connected by the labyrinth included Ganda Mnemma, Friedman, Oliandé, Centauri, Aloophoa and Shakespeare's Planet. (PROSE: Golden Age)