Sweden Finland. There are several connections from the Stockholm area across the Sea of Åland to Mariehamn in the Åland Islands as well as Turku and Helsinki on the Finnish mainland and beyond to Estonia and St Petersburg in Russia. Ferry routes from the Stockholm area also connect with Ventspils and Riga in Latvia as well as Gdańsk in Poland across the Baltic Sea. The ferry ports of Karlskrona and Karlshamn in southeastern Sweden serve Gdynia, Poland, and Klaipeda, Lithuania. Ystad and Trelleborg near the southern tip of Sweden have ferry links with the Danish island of Bornholm and the German
Finland–Sweden border in a topographical description made in 1811. The border was decided to run through the geographical centre of the island (defined by coordinates) in the treaty of Åland in 1921 and in the treaty of continental plates in 1972. The Märket lighthouse, built in 1885 by Finland and operated by them, was left on the Swedish side. In 1981, the border on the island was modified into a curve to get the lighthouse on the Finnish side. The border is agreed to be regularly inspected every 25 years. During the independence of Finland, inspections have been made in 1926–1927, 1956–1957,