Discworld
Check the behind the scenes section, the revision history and discussion page for additional comments on this article's title.
A world in the shape of a disc existed in a novel read by Izzy Sinclair. It had the city named Ankh-Morpork and was home to a character named Granny Weatherwax.
Izzy asked the Eighth Doctor if they could visit the world. The Doctor replied that he'd been there, and it was "flat". (COMIC: Fire and Brimstone (part 1) [+]Loading...{"page":"15","part":"1","1":"Fire and Brimstone (comic story)"})
Behind the scenes
While not explicitly named in Fire and Brimstone (part 1) [+]Loading...{"page":"15","part":"1","1":"Fire and Brimstone (comic story)"}, this is Discworld from the Discworld novel series by Terry Pratchett.