That would probably be due to the Nordic passport union[1]. Locals have been able to travel between the countries freely without a passport since 1954. [1h] h

That would probably be due to the Nordic passport union[1]. Locals have been able to travel between the countries freely without a passport since 1954. [1h] https://en.m.wikipedia.org/wiki/Nordic_Passport_Union https://en.m.wikipedia.org/wiki/Nordic_Passport_Union