Arctic Circle
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The Arctic Circle is one of the two polar circles, and the most northerly of the five major circles of latitude as shown on maps of Earth at about 66° 34' N. Its southern equivalent is the Antarctic Circle.
Polcirkeln portal in Gällivare, Sweden
Arctic Circle line in Rovaniemi, Finland c. 1865
Arctic Circle monument in Salekhard, Russia
Mirage
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A mirage is a naturally-occurring optical phenomenon in which light rays bend via refraction to produce a displaced image of distant objects or the sky. The word comes to English via the French (se) mirer, from the Latin mirari, meaning "to look at, to wonder at".
An inferior mirage seen in the Mojave Desert in a Nevada spring
A hot-road mirage, in which "fake water" appears on the road, is the most commonly observed instance of an inferior mirage.
Heat haze seen through exhaust gas from a jet engine
Above: A superior mirage of a plane on ice, McMurdo Station Below: An artificial mirage, using sugar solutions to simulate the inversion layers.