Arctic Circle level, although in mountainous regions there is often no direct view of the true horizon. Only four million people live north of the Arctic Circle due to the severe climate; nonetheless, some areas have been settled for thousands of years by indigenous peoples, who today make up 10% of the region's population. Tens of thousands of years ago, waves of people migrated from eastern Siberia across the Bering Strait into North America to settle. The largest communities north of the Arctic Circle are situated in Russia, Norway and Sweden: Murmansk (population 307,257), Norilsk (175,365), Tromsø (71,295), Vorkuta (59,231) and Kiruna
City Circle Line City Circle Line The City Circle Line () or M3 is a future loop line of the Copenhagen Metro. It has been claimed by COWI A/S that the City Circle Line is the largest construction project to have taken place in Copenhagen during the last 400 years. Upon its completion, the network's total length shall be 43km and have 17 stations. Its completion has been anticipated to occur around the summer of 2019. Plans for its construction were approved by the Danish Parliament on 1 June 2007. Preferred bidders were announced during November 2010. The total cost was estimated at