Add Yahoo as a preferred source to see more of our stories on Google. The classic, matte blue is reminiscent of a seafaring tradition where maps with large swaths of blue led the way. We're well over ...

You're by the water's edge, observing a turquoise lagoon, then a little further away, you see an almost black sea at the foot of a cliff. Why does the ocean take on such different hues, from deep dark ...