Ice pillars over Finland

Photo: Timo Newton-Syms/Flickr

Thin, colorful ice pillars appear in the night sky above Ruka, Finland.

This stunning visual phenomenon occurs when light reflects off horizontally-faced ice crystals hovering in the air. The pillars, which are often mistaken for UFO sightings, are produced by sunlight, moonlight or artificial manmade light situated along the horizon.

Like auroras, this beautiful light display is only visible in the coldest regions of the planet.

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Ice pillars over Granby, Colorado

Photo: Eric Magnuson/Flickr

Granby, Colo.

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Ice pillars over Moscow, Idaho

Photo: Jasper Nance/Flickr

Moscow, Idaho

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Ice pillars over Laramie, Wyoming

Photo: Christoph Geisler/Wikimedia

Laramie, Wyo.

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Ice pillars over Anchorage, Alaska

Photo: Nat Wilson/Flickr

Anchorage, Alaska

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Catie Leary is a photo editor at Mother Nature Network. Follow her on Twitter and Google+.