Transit of German troops through Finland and Sweden Union immediately requested a similar but more far-reaching concession from Finland, which invited the Third Reich to trade similar transit rights through Finland in return for weaponry lacked by the Finns. This was the first significant proof of a changed, more favorable, German policy vis-à-vis Finland, that ultimately would put Finland in a position of co-belligerence with Nazi Germany in the Continuation War against the Soviet Union (June 25, 1941 – September 4, 1944). After Denmark and Norway were invaded on April 9, 1940, Sweden and the other remaining Baltic Sea countries became enclosed by Nazi Germany and the Soviet
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,