Malmberget, 5 km north of Gällivare, sits on top of one of the largest iron-ore deposits in the world — and the mining has gone so deep and so widely that the town itself is being consumed. The crater known as Kaptensgropen, in the middle of what used to be central Malmberget, is now several hundred metres across. The mining company LKAB is steadily buying up and dismantling the surrounding buildings.
You cannot get into the active mine, but the LKAB mine visitor tour runs from June to August: a guided minibus down to a depth of 1,000 metres, into the disused workings, with explanations of the geology and the mining methods. It is a startling experience and worth booking ahead in summer.