"Amazon Abyss" explores the world beneath the surface of the Amazon River. Until this feature was filmed, no one had ever explored the depths of the Amazon due to the harsh conditions. The Amazon's swift and treacherous currents and dark water, stained by sediment, conceals ¼ ton Cayman alligators, stingrays, piranhas and anacondas. Veteran divers and naturalists braved the challenge to explore this new frontier.