The Floating Fountain of Guadlu

Describe a natural or constructed wonder in your world. What purpose does it serve and what is the significance behind it?

     About 600 thousand years ago the Mage's Brotherhood created the Vortex Lines, braking the minimal interference policy that characterizes the institutions during most periods of its History. There was no pressing crisis terrible enough to justify such an bold intrusion with the Vortex, but the mages did it anyway. Mostly as a consequence of internal power game. 
    If there was no crisis to justify the Lines, more than a few resulted from their placement. There was no much political intrusion in that particular, the only place where the lines could be is where they are, some details are arbitrary but the general design is not. It follow objective characteristics of Sharitarn magic. 
    During the centuries of confusion and war that followed the creation of those filters for the gifts of the Vortex many old nation disappeared and some new ones emerged. The most beautiful and influential among those new nations was certainly Guadlu, the City of Wonders. 
    The race responsible for set the basis for this nation had arrived recently to Sharitarn oceans. This merefolk race had advanced skills as builders, and a complex society highly based on hereditary magic. They gained the trust and respect of most talking races living on the sea at the time, and eventually expanded they portfolio of allies to some land-dweller nations. Guadlu was their cultural and political capital. 
    The bottom of the sea was about 600 meters deep in most the area close to the coast, but reached more than 10 kilometers deep in some scars and holes on the rock. The merefolk build vertical farms connected to the bottom that almost reached the surface, and from that they could feed not only their own people but most the intelligent nations of Sharitarn. Their city was initially placed on a flat plateau about 200 meters bellow sea surface, next to a vertical stone wall that raised up to 40 kilometers above the sea. 
     Merefolk dug this hard stone to create a safe harbor for their land dweller buyers and merchant partners. Also for their slaves and free employees. 
     Twelve thousand years after that Guadlu was a multi-cultural nation where lived citizens from more than two hundred different species. Some of them capable to breath only sea water, some only capable to breath air and unable to swim, and all imaginable variations in between. The growing above sea level had reached the top of the stone wall. Where existed a wild plateau covert by a large savanna.  
      The nations of the continent had interest in buy Guadlu products here, and transport them by road, instead of only have access to those items in the port bellow. Human nations where willingly to build roads, and even pay part of the costs to see the City of Wonders expanded to the surface. 
       That good will made possible the construction of the maze of hot pools in the surface, connected by rivers excavate on hard rock. A system of pools inside the ground lifts the ships from sea level all the way to the top, where they have access to the rivers and channels that take them to ports, deposits and the Main Market. And allow the Merchant Caravans to pick the products. 
      However, for all that work without an outrageous violation of the Exclusion Law some magic had to be provided. Teleportation was already lost, or almost completely so, the followers of this Way who still existed where not enough to solve a problem in that scale. 
       The alternative was the Floating Fountain. 
        It is a stone sculpture as large as a small castle that floats a dozen meters above the lake that is the origin of all rives and hot pools on High Gladlu. The part of the city know as Dream City. From openings in this sculpture fall a constant quantity of fresh water, at warm temperature. This substance is magically created. 
       Everything in around this floating fountain of life was designed to look marvelous and surreal. A dream image of prosperity and beauty.  
      The merefolk is mostly extinct and what is left of Guadlu now is a mere village. A human nation, under the protection of Lutianen. However, the Floating fountain still exists, and the lifting system still works (even if most of it isn't in use).