The Big Blue contains these five programs: The Big Blue, Under the Sea, The Underwater City, The Frontier of the Sea, and On the Seaside. Oceans cover 70% of the Earth's surface, but there is still much we do not know about them. Immerse yourself in this mysterious and miraculous world. From sea-beds and magnificent coral reefs to rocky cliffs and coastlines pounded by the sea, witness the ingenious ways in which a multitude of species adapt to their environments and fend off predators.