The Last Hero by Terry Pratchett (Discworld 27)

“The place where the story happened was a world on the back of four elephants perched on the shell of a giant turtle. That's the advantage of space. It's big enough to hold practically anything, and so, eventually, it does.”

Book twenty-seven is a bit of an anomaly. It’s a large book as far as its height and width, although not as thick as other Discworld books, barring Eric. It’s also lavishly illustrated by Paul Kidby, and is something of a graphic novel.