The Arctic Circle is an imaginary line of latitude located at approximately 66°33′ North of the Equator. It marks the southern boundary of the Arctic region. This latitude is determined by the 23.5° tilt of the Earth's axis. Astronomical Significance: -24 hours of daylight (Midnight Sun) – around 21 June (Summer Solstice) 24 hours of darkness (Polar Night) – around 21 December (Winter Solstice) This phenomenon occurs due to the 23.5° axial tilt of Earth. Countries Through Which the Arctic Circle Passes: - Norway, Sweden, Finland, Russia, United States (Alaska), Canada, Denmark (Greenland). Physical Geography of the Arctic Region: -Arctic Ocean at the center, Large sea ice cover, Tundra vegetation, Permafrost soils, Major islands: - Greenland, Svalbard, Canadian Arctic Archipelago. Important Wildlife: - Polar bear, Arctic fox, Reindeer (Caribou), Walrus, Seals, Snowy owl. (For more refer book MASTERING MAPPING By AskDepot)