Pygmy tribes describe an animal that resembles a sauropod dinosaur.

For over a century a sea serpent known as Caddy has been reported swimming off the coast of British Columbia.

The Amazon echoes with tales of a terrifying mystery beast known as the Mapinguari.

See the world through the eyes of some of nature's deadliest and most surprising predators.

Patrolling America's largest state is the job of roughly 400 troopers in one of the toughest law enforcement agencies in the nation. Essentially, these cops say, nearly every Alaskan resident is armed and they know how to use their weapons, which makes any scenario a trooper encounters a potentially fatal one. Follow along as the "blue shirt" Alaskan State Troopers police the towns and villages, and the "brown shirt" Alaska Wildlife Troopers enforce regulations covering both commercial and sport fishing and hunting activities.

"Move as millions. Survive as one." That's the catchphrase of this seven-part event for which a National Geographic team spent two-plus years recording across 20 countries and all seven continents. Narrated by Alec Baldwin, it tells the stories of many of the planet's species and the journeys they undertake to ensure their survival. The diverse range of animals shown -- many revealing behaviors never caught on film before -- include Botswana zebras, Mali elephants, flying foxes in Australia, Pacific white sharks, and the white-eared kob of the Sudan, thought to have been destroyed during decades of violence.

British adventurer and cinematographer Richard Terry travels to faraway jungles and remote islands in search of the truth behind stories of unknown creatures attacking, and killing, humans. In the Amazon rainforest, Terry is on the trail of a huge spider said to be attacking villagers; in southern Mexico, reports of a terrifying creature that attacks locals at night sends Terry into the jungles of Chiapas to investigate; and in the Indonesian archipelago, Terry island hops to expose a giant, blood-thirsty reptile that preys on livestock and humans.

Cameras follow the action along Arizona's Sonoran Desert, one of the busiest border crossings in the country, as officers and agents of U.S. Customs and Border Protection fight terrorism, apprehend drug smugglers and intercept people entering the United States illegally. The series also embeds with Customs and Border Protection, and with local law enforcement, as units patrol near and on the border in South Texas.