Overview: The sun and moon move billions of tons of water with every turn of the tide. The strongest tides empty entire bays, smash trees on riverbanks, and strand sea creatures on suddenly dry land. Weaker tides control the movements of huge numbers of fish, coaxing stingrays though astounding underwater arches. And as the water recedes, the tide can create unbelievable landscapes - like a sparkling world of salt crystals inhabited only by tiny shrimp and bright pink flamingos.