The Baltic Sea is the body of water lying between the Scandinavian peninsula and continental Europe.
The Baltic sea is connected to the North Sea via the Kattegat and Skaggerak between Sweden and Denmark.
The northern Baltic in particular is of extremely low salinity, being diluted by the run-off of many rivers and the heavy regional rainfall, permitting many freshwater fish, such as the pike, to inhabit its northern arm, the Gulf of Bothnia. Other important inlets are the Gulf of Riga and the Gulf of Finland. Much of the northern Baltic is frozen in winter.
Countries possessing Baltic coastlines are Sweden, Finland, Russia, Estonia, Lithuania, Latvia, Poland, Germany and Denmark.
Important cities and ports of the Baltic include Stockholm, Helsinki, Saint Petersburg, Tallinn, Riga, Gdańsk, Lubeck and Kiel.
The Baltic's largest island is Gotland.
Surrounded by a number of industrial cities, and with little mixing of its waters with other seas, the Baltic is amongst the most heavily polluted seas on Earth.