Thanedd by Jana Komárková

Thanedd in Czech book by Jana Komarková

Icon Island
The magical Thanedd Isle is located in the bay northwest of Gors Velen in Temeria, to which it is connected by a bridge. It is primarily the location of the academy for young adepts at magic. Thanedd is divided into three main areas:

All three parts were built by elves and are 'crowned' by Tor Lara. The island itself is hollow, like a shell. It can be accessed either by the bridge (the conventional route) or from the sea via the underground passages (a less traditional, though certainly stealthier way).

Andrzej Sapkowski Edit

The island seemed very close, and it didn't resemble an island. It looked like the base of a gigantic stone column stuck into the seabed, a huge ziggurat encircled by a spirally twisting road and zigzagging steps and terraces. The terraces were green with groves and gardens, and protruding from the greenery — which clung to the rocks like swallows' nests — rose soaring white towers and the ornate domes of groups of buildings framed by cloisters. The buildings gave no clue at all that they had been constructed from stone. They seemed to have been carved directly from the mountain's rocky slopes.
— pg(s). 66, Time of Contempt (UK edition)