What's the name of the agreement allowing free passage across northern European borders including the one between Finland and Sweden?
Finland–Sweden border The Finnish-Swedish border is the border between the countries of Finland and Sweden. Almost the entire border runs through water: along the Tornio River and its tributaries, and in the Gulf of Bothnia. Only a few kilometres of the border are on dry land. Because of the Schengen treaty and the Nordic Passport Union, the border can be crossed mostly freely.
Stena Line Stena Line is one of the largest ferry operators in the world. With services serving Denmark, Germany, Ireland, Latvia, the Netherlands, Norway, Poland, Sweden and the United Kingdom, Stena Line is a major unit of Stena AB, itself a part of the Stena Sphere. Stena Line also owns the Swedish vessels of the otherwise German- and Danish-owned Scandlines.