This structure comprises to circular buildings one inside the other, the radius of one being 25m. and other, 40m. The inner structure is fuor storeyed and outer, thee storeyed. Both the inner and outer structures have 13 windows surmounted by oval arches. The whole is surrounded by a high protective wall and there is a guardroom on its west side. During the Russian invasion of 1916-1918 it was used as an Arsenal and the roof was blown off by an explosion which took place on 9 July, 1919 .
TRABZON CASTLE
The city walls, the greater part of which are still standing, are among the city's oldest structures. Indeed, their oldest part can be daded back to the 5st century AD, that is the Roman Period. Historical sources provide information about older stages of their construction. Xenophon, who visit the city in the 5th century BC, also mentions the existence of city walls.
The walls of Trabzon can be divided into three parts that is Yukari Hisar (The inner stronghold). Yukari Hisar and Orta Hisar were founded on the towering mass of rocks between Kuzgun Creek and Imaret (Iskeleboz) Creek. This structure comprises the oldest part of the stronghold and could be described has roughly Trapezoid in shape.
The name of the city derives from the word “Trapez” or “Trapezus”, which means “Trapezoid”.