The Arctic Circle is the southern latitude where the midnight sun can be seen at the summer solstice.
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During a period of 40,000 years the Arctic Circle moves southwards and northwards within an area 180 km wide (A). During a period of 18,6 years, it also moves within an area 570 m wide (B).
The Arctic Circle will reach its northernmost position in the year 12,000, return here in 22,000, to reach its southernmost position in 32,000 and so forth.