Here we see the tower in silhouette above the glen.
Nobeing knows what race built the tower.
Although legend says that humans from the First Universe built it to incarcerate a traitor who sold the secret of the Starportals to the Weee.
We do know that in the distant past the Weee found their way through the gates and managed to decimate most of the Milky Way galaxy before they were stopped on a world called Mercury in that galaxies Sol system.
And if the wizards of Earthsea know, they are not giving any information out, course, ………..thats the way of wizards!!