Moving house is a complicated ordeal that can take thousands of dollars and many weeks to organise. Try moving half a town. The Arctic town of Kiruna, Sweden's northernmost municipality, is under threat as cracks caused by decades of iron ore mining slowly erode its foundations, according to Reuters. So two years ago the municipal council decided to move more than half of the town from the shadow of Kiirunavaara mountain, site of the world's largest underground mine. This month it chose the new site for Kiruna's centre, at the base of Luossavaara mountain, about 4 km (2.5 miles) away. The town's deputy mayor puts the cost of moving the buildings at about 30 billion Swedish crowns ($4.28 billion), not including rerouting the railway and roads. The council also hopes to win government approval for a 2-billion-crown tunnel to keep the railway from dividing the new town. LKAB, the state-run firm that owns the mine, said the move was essential if it was to access the estimated 800 million tonnes of crude ore still in the ground. "If a decision would have been made not to move the town, that would also have been a decision to close the mine," said Goran Olovsson, who oversees mining legal issues at LKAB Kiruna.