It starts like this:
"Through the deeps of space swims the star turtle Great A'Tuin. It's ten thousand miles long, its shell is pocked with meteor craters and frosted with comet ice. On its back it's bearing the four giant elephants who carry on their shoulders the mass of the vast, glittering, waterfall-fringed circle of the Discworld.
A tiny sun and moon spin around the Discworld, and probably nowhere else in the multiverse it is sometimes necessary for an elephant to cock a leg to allow the sun to go past. Possibly the Creator of the Universe got bored with all the usual business of globes, axial inclinations and rotational velocities, and decided to have a bit of fun for once…" (Terry Pratchett, The Discworld Series Introduction)
Want to know more? Go to my Discworld Reader’s Guide!