I have a new theory. Wano is not on the back of a turtle nor it was pulled together by continent pullers. Zunisha was at the location for 5-6 days in the past and every time she took a dump, a new part of the island was formed. Human’s moved onto the shit and created settlements. Because it was rich in manure, the country that developed was very green in the past. That’s also how Wano produced some green headed swordsmen.