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 man-made light situated along the horizon.
Granby, Colorado (Photo: Eric Magnuson/Flickr)
Moscow, Idaho (Photo: Jasper Nance/Flickr)
Laramie, Wyoming (Photo: Christoph Geisler/Wikimedia)
Anchorage, Alaska (Photo: Nat Wilson/Flickr)