By day, a red tide is unsightly and uninviting, with water the color of coffee. But at night, during this unusual phenomenon caused by a plankton bloom, the waves are a brilliant, almost neon blue. This wonderfully surreal scene has played out almost nightly along San Diego beaches for several weeks, luring spectators with cameras and video recorders.
Watch: Beautiful waves crashing
Full story: Electrifying blue waves luring awe-struck crowds to San Diego beaches