A magic pearl that creates a quantity of drinkable water when sucked upon or stirred about in a liquid.
The city of Nausopol is built on stilts. Lots of very sturdy stilts and butresses, of course, because it rises about five hundred feet from the ocean. Even the most terrific of storms is only heard in the city as a distant cacophony of blasts as waves strike the solid stonework fathoms below. It has never been attacked because of its isolation and impregnability.
It's not a place for the faint-hearted: vertigo and sea-sickness are not desirable traits. But when you are standing in the middle of the city there is no way you could tell that you were standing above an ocean, separated only by a gulf of air and a few stones.
A thousand steps lead down from Nausopol to the floating docks. These docks are pitch-coated wooden and can be raised by winches during squalls. Trade with other cities and countries is good: Nausopol is built over a sunken atoll whose minerals are still mined by divers, and it was from this that it originally derived its wealth.
But the principal method of getting to and from the city is by riding the giant sea-eagles which have been captured and bred for that very reason.