arctic

The Arctic includes the large sea ice covered Arctic Ocean, surrounded by the northernmost parts of North America and Asia. The Arctic can be defined as everything north of the Arctic Circle at 66° 33'N, or it can also be defined as the region where the average temperature for July is below 10 °C (50 °F). The tree line follows this isotherm fairly closely. The Arctic has been home to many indigenous cultures for thousands of years. The region includes portions of the nations Canada, Russia, Greenland, United States, Norway, Sweden, Finland, and Iceland.