Yeah, I don't normally link to Wikipedia here. But I came across this recently when looking something up and it really sucked me in. Having spent 25+ years of my life reading this series, some of the books 5–10 times, I consider myself to have a fairly intimate knowledge of the story.
But the Wikipedia entry introduced some concepts that were new to me right from the start:
The series is set in an unnamed world that, due to the cyclical nature of time as depicted in the series, is simultaneously the distant past and the distant future Earth.
The series depicts fictional, ancient mythology that references modern Earth history (with one notable example being the legend of two giants named Mosk and Merk, who were said to fight wars against each other using spears of fire that could reach around the world), while events in the series prefigure real Earth myths (with King Artur Paendrag Tanreall, better known as Artur Hawkwing, serving as an allusion to the myth of King Arthur Pendragon).
I have never thought of this story as been placed on our earth. It's funny how people perceive things differently. Anyway, whether this is actually true or not, I enjoyed getting sucked in.
It might be time for a complete series re-read.