 75,000 WWI prisoners of war who so badly injured that they were exchanged between the warring sides and 27,000,000 kg of mail, mostly from or to prisoners of war, was sorted at Haparanda.Haparanda is connected to the Swedish national network by the Haparandabanan (Haparanda railway).The bridge between Haparanda and Tornio is the only direct connection between the Swedish and Finnish rail systems.