Here is a photo of a stunning a sun-pillar captured at sunset near Jenison, Michigan on April 10, 2012.
Sun Pillars occur typically during sunrise or sunset; when sunlight is reflected off the surface of falling ice crystals associated with thin high-level clouds, like Cirrostratus clouds.
The crystals are hexagonal, plate-like crystals and as they fall they are forced into a horizontal orientation due to resistance from air.
The result is the reflection of this beautiful pillar of light.
Image Credit: Kevin Povenz