The Baltic Sea borders Sweden, Finland, Denmark, Russia, Estonia, Latvia, Lithuania, Poland and Germany. The Baltic Sea is an arm of the northern Atlantic Ocean that separates the Scandinavian Peninsula from the rest of Europe.
Covering around 149,000 square miles, the Baltic Sea touches around 5,000 miles of coastline. The exact dimensions of the Baltic Sea are fluid, but its waters are generally agreed to start somewhere around Kattegat Bay west of Denmark. It includes the gulfs of Gdansk, Bothnia, Finland and Riga. Because it connects so many disparate areas of Northern Europe, it was the economic core of the Hanseatic League, an economic alliance of the late Middle Ages. It still represents an important trade route over which countries in the region ship natural resources and manufactured goods. The bordering countries also rely on the sea's beautiful beaches as a summertime attraction for tourists. In addition to the countries that border it, the Baltic Sea also drains a number of countries that do not border it: the Czech Republic, Belarus, Norway, Slovakia and Ukraine. Composed largely of brackish water that is saltier than freshwater but less salty than typical ocean water, the Baltic Sea is of great interest to scientists who explore its unique flora and fauna.