Brazil — The Amazon Basin: Giant Anaconda

Josh brings his team to Sao Paulo, Brazil, in search of the much-reported giant anaconda. Their hunt begins with a visit to Dr. William Ernest, coordinator of biodiversity research at Inpa. Dr. Ernest explains that with 96 percent of the Amazon rainforest left unexplored, new species of life are found there all the time.

Similarly, Dr. John Francisco of the Manaus Snake Research Center says the biggest anaconda recorded to date is about eight meters (25 feet) long, but it's possible that something larger might be out there. Before leaving for the rainforest, Josh enters a pit and handles an anaconda to give himself a sense of what he might be getting into.

Traveling in a series of progressively smaller boats, the team penetrates the Amazon rainforest. Along the way, Josh visits small villages, where eyewitnesses have reported encounters with the giant reptile. One man shows Josh the makeshift harpoon system he built with a tree branch and an empty soda bottle, and then he bequeaths it to Josh to aid in his hunt for the creature.

That night, Josh and his team begin exploring one of the river's many tributaries where reports have been prevalent. During the night, the team is fascinated while watching a small, poisonous snake work its way up a tree branch, inching closer to a small bird that refuses to fly away. Brad begins to freak out when he realizes they have come without anti-venom to an area crawling with lethally poisonous insects, arachnids and reptiles that can strike from the darkness with no notice.