Zilkale

Zilkale is a medieval castle located in the Fırtına Valley within the Pontic Mountains, and is one of the most important historical structures in the Çamlıhemşin district of Rize Province, within the Black [Sea Region] of Turkey.
The castle is built at an altitude of, and sits at the edge of a cliff overlooking the Fırtına River approximately below, running at an elevation of southeast of it.
In the 1st-4th centuries AD it was the capital of the Laz principality of Macron-Henochi. The castle consists of the outer walls, middle walls and the inner castle. There are garrison quarters, and a possible chapel and head tower.

Etymology

Zilkale: Zil means "bell" and kale means "castle" in Turkish.
Alternatively:

Zirkale: Zir means "lower" in Persian and kale means "castle" in Turkish.