Sevastopol , sometimes written Sebastopol, is the largest city in Crimea and a major port on the Black Sea. Due to its strategic location and the navigability of the city's harbours, Sevastopol has been an important port and naval base throughout its history. Since the city's founding in 1783 it has been a major base for Russia's Black Sea Fleet, and it was previously a closed city during the Cold War. The total administrative area is 864 square kilometres and includes a significant amount of rural land. The urban population, largely concentrated around Sevastopol Bay, is 479,394, and the total population is 547,820.