4. Gorillas

Charlotte Uhlenbroek travels to Uganda where she encounters rare mountain gorillas in the Bwindi Impenetrable Forest. With only 600 of the creatures left in the world, this protected habitat is one of the few remaining places where they can still be found in their natural environment. The expedition is threatened by bad weather and faulty equipment, but the expert's tenacity pays off when she comes face to face with a silverback and its large family.