Of course, no other world was carried through the starry infinity on the backs of four giant elephants, who were themselves perched on the shell of a giant turtle. His name - or her name, according to another school of thought - was Great A'Tuin; he - or, as it might be she - will not take a central role in what follows but it is vital to an understanding of the Disc that he - or she - is there, down below the mines and sea ooze and fake fossil bones put there by a Creator with nothing better to do than upset archaeologists and give them silly ideas.