A film of the 2,000-mile Geographical Magazine hovercraft journey through some of the remotest waterways of the Brazilian and Venezuelan rain forests, including the dangerous Maipures and Atures rapids.

The leading figure in sea exploration is on a five-year voyage which is the culmination of his life's work. On board his ship Calypso he has a team of scientists equipped with some of the most advanced oceanographic apparatus yet devised, including miniature submarines and underwater film and television cameras.
In this the first of several film reports Cousteau turns his attention to the most feared of all the inhabitants of the sea...