The Arctic Circle

Now, this card is indeed very interesting. It was sent to me by Tonni who lives north of Oslo. The card shows the monument indicating the Polar Circle latitude 66° 33′  . The Arctic Circle Centre is situated by the E6 h ighway at Saltfjellet in the county of Nordland. It is also situated in a national park with wonderful hiking opportunities.

In the area around the centre, there are Russian and Yugoslavian war memorials from World War II. The centre's architecture is adapted to the surrounding nature, and a path made of marble shows how the Arctic Circle runs through the centre. 
At the centre you will find a cafeteria serving Norwegian food, a large souvenir/gift shop and an exhibition covering art, marble and stuffed arctic animals - including Europe's largest stuffed polar bear. There is an excellent movie theatre showing the multi-vision programme "Northern Norway". You will find a post office selling postcards with a special Arctic Circle seal. The Arctic Circle Centre is open from 1 May to 15 September.

The Arctic Circle is one of the five major circles of latitude that mark maps of the Earth. In 2012, it is the parallel of latitude that run 66° 33′ 44″ (or 66.5622°)  north of the Equator.

The region north of this circle is known as the Arctic, and the zone just to the south is called the Northern Temperate Zone. The equivalent polar circle in the Southern Hemisphere is called the Antarctic Circle.

The Arctic Circle is the southernmost latitude in the Northern Hemisphere at which the sun can remain continuously above or below the horizon for 24 hours (at the June solstice and December solstice respectively). North of the Arctic Circle, the sun is above the horizon for 24 continuous hours at least once per year (and therefore visible at midnight) and below the horizon for 24 continuous hours at least once per year. On the Arctic Circle those events occur, in principle, exactly once per year, at the June and December solstices, respectively.

It would therefore seem that the Arctic Circle marks the southern extremity of the northern hemisphere polar day (24-hour sunlit day, often referred to as the midnight sun) and polar night (24-hour sunless night). In fact, because of atmospheric refraction and mirages, and because the sun appears as a disk and not a point, part of the midnight sun may be seen on the night of the northern summer solstice up to about 50′ (90 km (56 mi)) south of the Arctic Circle; similarly, on the day of the northern winter solstice, part of the sun may be seen up to about 50′ north of the Arctic Circle. That is true at sea level; those limits increase with elevation above sea level although in mountainous regions, there is often no direct view of the true horizon.

The position of the Arctic Circle is not fixed. It directly depends on the Earth's axial tilt, which fluctuates within a margin of 2° over a 40,000 year period, notably due to tidal forces resulting from the orbit of the Moon. The Arctic Circle is currently drifting northwards at a speed of about 15 m (49 ft) per year.