World's Strangest Natural Wonders
Lake Retba, Senegal
It looks as if someone poured a giant bottle of Pepto-Bismol into Lake Retba—that’s how deeply pink these waters are. The color is actually caused by a particular kind of algae called Dunaliella salina that produces a pigment. The salt content is extremely high, reaching 40 percent in some spots and allowing the algae to thrive (and swimmers to float effortlessly on the surface of the 10-foot-deep lake). Blinding white piles of salt line the shores, and locals work several hours a day harvesting salt from the bright pink water.