Complex sentence: In the Oz stories, Baum states that the Emerald City is the most dazzling place on earth, the equal of which has never been seen or yet discovered (even in other fairylands).
Split into simpler sentences: In the Oz stories, Baum states that the Emerald City is the most dazzling place on earth. The equal of which has never been seen or yet discovered (even in other fairylands).