1940-1945 39-45 40-45 armies army base battlefield boat boats building buildings bunker city coast de europe european fishing fortified france french front german harbor harbour heritage historic historical ii kriegsmarine la landscape landscapes loire loire-atlantique monument monuments nazaire patrimony pays pen pens port ports saint saint-nazaire sea second ship ships st st-nazaire St. submarine submarines tourism town travel two u-boat u-boats war wars world ww2 wwii