Particularly after Norwegian independence (from the United Kingdoms of Sweden and Norway) in 1905, the Norwegian authorities were insistent that all should speak Norwegian only and schools became active tools of assimilation. The Sami language was banned in schools, churches and in public administration. Concerns about possible Finnish irredentism also led to increasing pressure on Kvens to assimilate. People who wanted to buy state-owned land in Finnmark had to prove they could speak Norwegian before they were allowed to settle. This region of Norway was the area most affected by World War II. In 1940, the Norwegians and Allied forces fought the German Army to a standstill over the strategic port for iron exports of Narvik, until allied forces and equipment were withdrawn, leaving the remaining Norwegians with no option but surrender. King Haakon VII and the government fled towards the north, and stayed in the Tromsø area for three weeks. On 27 May, Bodø was bombed by the Luftwaffe, and on 7 June, the Allies retreated from the North, and the King and government fled to Britain from Tromsø. During the war, the area was used by the Kriegsmarine to stage U-boat attacks on Allied Arctic supply convoys resupplying the Eastern Front. In 1944, the German Wehrmacht started to retreat from the Murmansk front. They burned everything after them in the area between the Russian border and the Lyngen fjord, as part of their tactics. The population was forcibly evacuated, although a third of them chose to hide in the wilderness instead. All who were found were shot. After World War II, Norway made a huge effort to rebuild the destroyed towns and villages. Modernizing fishing and agriculture was important, as Northern Norway was considerably poorer and less developed than the south. In 1946, the huge steel works of Mo i Rana were founded, heralding industrialization of the north. Transportation was also improved, as airports were built throughout the area, notably in Bodø in 1952 and Tromsø in 1964. The rail network was extended to reach Bodø in 1961. In 1972, the University of Tromsø opened, accompanied by a number of university colleges, notably in Bodø, Alta, Harstad and Narvik. In 1972 and 1994, the strong anti-EU movements of the north, largely based on concerns over EU mismanagement of its own fish stocks, were instrumental when Norway voted against EU membership in referendums. Sami language instruction was introduced in