The hydro-electric power station at Porjus, 100 km S of Kiruna, was one of the factors which made it possible for people to live and mine iron ore north of the Arctic Circle. The power station, designed by Erik Josephson, was completed in 1914. It derived its power from water impounded by a 1250 m dam, and was the first major plant to have underground generation halls. At its peak it had an output of 530 MW, most of which was applied to power the railway linking Lulea with Kiruna and Narvik. Josephson’s power station, now replaced by a modern plant, serves as a museum, and as a training facility for electrical engineers. The museum is a popular attraction in the Laponia (Lappland) National Park, which is a UNESCO World Heritage Site.