Arkannis Major

Arkannis Major, also known as Colony world 4378976.Delta-Four, was a planet far away from Earth. It was colonised by humans by 2775, by which time it had a population of 20 million. Its inhabitants knew it by many names, such as Journey's End, Discovery, and Pioneer.

Due to micro-organisms in its atmosphere, anyone living on the planet started to believe things they imagined (as well as fictional works) were real, resulting in the outlawing of fiction in the planet's only city. (PROSE: The Stealers of Dreams)