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.