Sun halo over Lake Antermoia in the Dolomite Mountains of Italy. Sun halos form when sunlight shines through ice crystals suspended in the upper atmosphere. When the light of the sun hits the crystals they serve as a prism, separating the light into individual colors of the spectrum, the same way rainbows occur after a rain shower.

For other images of atmospheric halos in this group, please view:

zafoid.com/post/view/12634
zafoid.com/post/view/12624
zafoid.com/post/view/3110