WW 2 submarine, Unesco world heritage site Suomenlinna sea fortress, Helsinki, Finland, Europe

1939 1945 boats boat buildings building capital city capitals capital castles castle cultural monuments cultural monument cultural sites cultural site deserted empty europe famous place finland finnish fortifications fortification fortresses fortress helsinki heritages heritage historical historic history nobody no one no people northern europe north europe place of interest scandinavia second world war sights sight submarines submarine suomenlinna suomi tourist attractions tourist attraction travel photography travel unesco world heritage sites unesco world heritage site uninhabited viapori world heritage site world war ii ww ii