Astronomical Significance: - The Antarctic Circle exists because of the 23.5° axial tilt of Earth. 1. December Solstice (around 21 Dec) (Sun remains visible for 24 hours within the Antarctic Circle (Midnight Sun) 2. June Solstice (around 21 Jun) (Sun does not rise for 24 hours (Polar Night) Climatic Importance: - Extremely cold polar climate, Long periods of darkness in winter, Long daylight in summer, Presence of permanent ice sheets, Antarctica is the coldest continent on earth Major Research Stations Near / Inside the Antarctic Circle: - Amundsen–Scott South Pole Station (USA), Vostok Station (Russia), Dakshin Ganga (India), Maitri Station (India), Bharati Station (India)