Jeremy Wade is with a commercial fishing boat in Alaska searching for giant halibut.

Jeremy heads to Australia to investigate a terrifying underwater attack by a 6-foot beast in a remote Outback river.

Fisherman and adventurer Jeremy Wade travels to Alaska to discover what has happened to the king salmon.

Fisherman and adventurer Jeremy Wade travels to Lake Garda in northern Italy to investigate a 16th-century monster fish.

Biologist Jeremy Wade ventures deeper into the baffling, unsolved mysteries beneath the water's surface.

Popular Animal Planet personality Jeremy Wade, the nine-season star of the network's top-rated series "River Monsters," returns to waterways across the globe to investigate reports of the unimaginable and unexplained. He takes viewers on journeys beneath the water to remote areas, to islands lost in time and out into the open ocean to investigate reports that include entire fish species suddenly disappearing; unexplained sightings of mythical beasts; once thriving rivers now empty; and genetic oddities that may have produced the biggest monsters yet.

Jeremy Wade's most extraordinary cases.

There appears to be dramatic evidence that some of the world's most iconic rivers are in declining health. Biologist, extreme angler and Animal Planet favorite Jeremy Wade ("River Monsters") investigates the disappearance of freshwater giants from the planet's largest waterways. He talks with people who live along the Amazon, the Ganges, the Yangtze, the Mississippi, the Danube and the Zambezi to understand how exploitation and pollution have degraded these rivers that were once home to his beloved monster fish. By gathering evidence, Jeremy learns about the rivers' health and sustainability and what is being done to save them.

Jeremy Wade is not a fisherman; he's an "extreme angler" in search of the biggest and most dangerous freshwater fish, the kind with a taste for human flesh. This action-adventure series also features Wade illustrating how these river monsters are constructed to kill.

Long-lost footage of a young Jeremy Wade searching for freshwater monsters.

Extreme angler Jeremy Wade goes in search of the biggest and most dangerous fish.

Before heading off on his next journey, Jeremy Wade counts down the biggest catches in "River Monsters" history.

Before Jeremy returns to the Amazon River in "Mighty Rivers," relive some of his most thrilling Amazon adventures, as he tangles with giant Arapaima and the mystery of the Water Mama.