Ultimate predators of the Amazon rainforest, black caiman grow over twenty feet long and weigh in at one ton. Seeing these massive reptiles in the wild would send most people running in the other direction, but filmmaker and biologist Rainer Bergomaz and forest ranger Yung Sandy are on a mission that will bring them closer to these behemoths than anyone has ever dared before. Take a thrilling journey up Guyana's Essequibo River as these wildlife experts leave civilization in their wake and enter the lair of the Amazon Basin's most feared predator. (Source: The Smithsonian Channel)