Schooling fish and whale shark
a Roman aqueduct at twilight, Segovia
a tourist viewing San Marco Basin, Venice, Italy
a skink tail, Tennessee
a translucent goby, Pacific Ocean
dog jumping into a lake, Spain
A peacock spreads his train
a painted violin, Asheville, North Carolina
Aerial view of island lagoon
Penguins line the edge of an iceberg
Frosted fern leaves
Courtyard of an Iranian mosque
Patterns in azurite
Polar bear jumping in the Arctic
Swimmers descend a curvy waterslide
Feet of a blue-footed booby
Veiled woman in doorway
Well-lighted igloo on an Arctic night
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Whale SharkThe sweeping color of sea and sky, blue is a common thread in nature, seen in the cerulean of a whale shark (pictured here), the indigo of a stormy night, and the cobalt of a peacock's feathers. Over the centuries, the hue has come to represent calm, cold, mysticism, and sadness.(For more pictures of the amazing colors of our world, buy the National Geographic book Life in Color.)
Photograph by Brian Skerry

Life in Color: Blue

See photos of all shades of blue, from National Geographic.