Tashan

An ancient city within the Sultanate of Osmany. It is the seat of the Tashan Vizirate, ruled by Devlian Barss. The city is set in the ground, a multi-level underground city, large enough to shelter 20.000 people together with their livestock and food stores, connected by vertical staircases and able to be closed from the inside with large rolling stone doors. It consists of three ringed layers, each able to be closed off separately, and holds housing and production complexes, such as wineries, oil presses, stables, cellars, storage rooms, refectories, and vaults. 
Tashan is reportedly one of three underground cities said to have been built in Ancient Chorene, by unknown makers, the largest and most prominent one allegedly being the legendary Ringwell. Its location has, however, been lost to time. The location of the third is believed to have been beneath the crumbling crags of the High Passes near Guzlok.