Akkerman fortress of Belgorod-Dnestrovskiy is one of Ukraine's biggest strongholds. Built on the place of ancient city Tira, main material is limestone. Is surrounded by moat having 14 m in width and 20 m initial depth. The fortress has form of irregular polygon in plan, and has area slightly over 9 hectares. Its walls spread over 2.5 km, the height of towers and walls is from 5 to 15 meters, and thickness 1.5 - 5 m. The stronghold initially had 34 towers, 26 of them are extant. 12 of them are hollow and were used as living spaces intended for defence and as grain storages.
The fortress is supposed to be built in the end of the XIV century, moldavian period in Belgorod-Dnestrovskiy history. At that times the stronghold was part of system of fortifications that protected the ways inside the Moldavian principality. In XV century the fortress is rebuilt and strenghtened, getting its final look after turkish reconstructions in XVI-XVIII centuries.
The citadel having over 300 m² in square is situated in the center of the fortress and is probably built by the Genovese in the end of XII century. The citadel has 4 strongest towers which have 5m thick walls and initially were up to 20 meters high. Citadel was the billeting place of the fortress governor, there also were governor's headquarters, powder magazine, city treasury and governor's guards. The citadel was unassailable.
In 1484 the Turkey captured the fortress after several abortive attempts. After that, the fortress was annexed by Ottoman empire and renamed as Akkerman (the White Fortress). The Russian forces captured the city and the fortress several times, in 1770, 1179 and 1806, but the city was annexed by Russia only in 1812 according to Bucharest peace treaty. In 1832 the fortress lost its sense as defensive installation, in 1896 it gained the status of architectural monument.
Near the fortress one can see the remains of ancient city Tira (founded in VI century BC by people that came from Milet)