Overview:David Attenborough continues his journey along the Zambezi River. This episode begins at Victoria Falls, the largest waterfall in the world. At the foot of the falls, with its moist climate, a wealth of plants and animals can be found, such as hyraxes. To coax the hyraxes out of hiding, David Attenborough illustrates why taking a dog whistle with you while on an African adventure is a very good idea indeed. Other highlights encountered on the way include an estivating lungfish and a herd of elephants washing and dust bathing at a water hole.Further along his journey David Attenborough explores a Portuguese fortress at Tete, believed to have been built over 400 years ago, and assesses the impact of the then newly constructed Kariba Dam, one of the largest dams in the world, on the displaced Tonga people and surrounding countryside.