People understand the value of taking the time to "stop and smell the roses", but how often do we think to stop and look up at the sky? Too often the beauty of the sunrise or sunset goes unnoticed, perhaps because we know they happen every day. And while we delight in the colours of a rainbow after a storm, not many people realize that prisms of colour can appear in the sky during certain times of day, under specific atmospheric conditions, too. Sun dogs, haloes, pillars and arcs occur more frequently than people realize, and are caused by tiny ice crystals in the atmosphere refracting and reflecting light. Such displays range from the familiar halo around the sun or moon to rare and breathtaking events when the whole sky is lit up by intricate coloured arcs.