Crocodiles are an animal we fear, and with good reason - they kill hundreds of people each year. Gordon Buchanan journeys up Papua New Guinea's remote Sepik River to meet the remarkable tribes who have learnt to live with these terrifying reptiles. Crocodile hunters invite Gordon to join them catching adult crocodiles with their bare hands, and Gordon meets a tribe who believe a giant crocodile protects them from their human enemies. Does Gordon trust the tribe enough to swim in the giant crocodile's lake?

• Gordon Buchanan