Geography of Russia , the Russian border is the world's longest. Along the 20,139-kilometer land frontier, Russia has boundaries with 14 countries: Norway, Finland, Estonia, Latvia, Lithuania, Poland (via the Kaliningrad Oblast), Belarus, Ukraine, Georgia, Azerbaijan, Kazakhstan, Mongolia, the People's Republic of China and North Korea. Approximately two-thirds of the frontier is bounded by seawater. Virtually all of the lengthy northern coast is well above the Arctic Circle; except for the port of Murmansk—which receives currents that are somewhat warmer than would be expected at that latitude, due to the effects of the Gulf Stream—that coast is locked in ice much of the
Arctic Circle occur, in principle, exactly once per year: at the June and December solstices, respectively. However, because of atmospheric refraction and mirages, and also because the sun appears as a disk and not a point, part of the midnight sun may be seen on the night of the northern summer solstice up to about 50 minutes (′) () south of the Arctic Circle; similarly, on the day of the northern winter solstice, part of the sun may be seen up to about 50′ north of the Arctic Circle. That is true at sea level; those limits increase with elevation above sea