Finland–Sweden border border continues south into the northern Baltic Sea to a point where it meets the zone border of Estonia. The tripoint between the economic zones is defined by a treaty signed in 2001. The Finnish–Swedish border was created in 1809 by the Treaty of Fredrikshamn, as Sweden ceded Finland over to Russia. The course of the border was described in the fifth article of the treaty, without great detail. The borders were agreed to be the Sea of Åland, the Gulf of Bothnia, and the rivers Tornionjoki and Muonionjoki. Islands in the sea belonged to whichever country was the nearest
Germany–Poland border Treaty of Warsaw, and by reunified Germany, in 1990 in the German–Polish Border Treaty of 1990. It was subject to minor corrections (land swaps) in 1951. The borders were partially open from 1971 to 1980, when Poles and East Germans could cross it without a passport or a visa; it was however closed again after few years, due to economic pressure on the East German economy from Polish shoppers and the desire of the East German government to diminish the influence of the Polish Solidarity movement on East Germany. Following the fall of communism in Poland and Germany, and the