Planeta Tierra es una aclamada serie de documentales creada por la BBC que nos muestra, en 11 episodios escritos por el prestigioso naturalista David Attenborough, la belleza de nuestro enorme planeta con imágenes nunca antes vistas. 3. "Fresh Water" UK broadcast 19 March 2006, 8.83 million viewers (32% audience share); US broadcast 15 April 2007 The fresh water programme describes the course taken by rivers and some of the species that take advantage of such a habitat. Only 3% of the world's water is fresh, yet all life on land is ultimately dependent on it. Its journey begins as a stream in the mountains, illustrated by Venezuela's Tepui, where there is a tropical downpour almost every day. It then travels hundreds of kilometres before forming rapids. With the aid of some expansive helicopter photography, one sequence demonstrates the vastness of Angel Falls, the world's highest free-flowing waterfall. Its waters drop unbroken for nearly 1,000 metres (3,000 feet) and are blown away as a mist before they reach the bottom. In Japan, the water is inhabited by the biggest amphibian, the two-metre long giant salamander, while in the northern hemisphere, salmon undertake the largest freshwater migration, and are hunted en route by grizzly bears. The erosive nature of rivers is shown by the Grand Canyon, created over five million years by the Colorado River. Also featured are smooth coated otters repelling mugger crocodiles and the latter's Nile cousin ambushing wildebeest as they cross the Mara River. Roseate spoonbills are numerous in the Pantanal and are prey to spectacled caiman. In addition, there are cichlids, piranhas, river dolphins and swimming crab-eating macaques. Planet Earth Diaries shows how a camera crew filmed a piranha feeding frenzy in Brazil — after a two-week search for the opportunity.