Allagash River, Maine
Photograph by Michael Melford, National Geographic
With the help of a camera technique, foam churned up by rapids traces strokes of silver on the surface of the Allagash River. Since 1970, 92.5 miles of the legendary Maine waterway have been protected under the Wild and Scenic Rivers Act.
(For more pictures of the amazing colors of our world, buy the National Geographic book Life in Color.)