Frogs are vanishing in America’s heartland. Canadian beluga whales are mysteriously dying in the Saint Lawrence River. Swarms of sea stars are overrunning parts of Australia's Great Barrier Reef. Has water become a massive delivery system for pollutants? National Geographic reveals signals that something is amiss in Earth’s water. Hosted by Edward Norton.

North America's freshwater seas are jewels of the continent that have been squandered by decades of human abuse. Today, concerned groups attempt to repair past damage and confront new threats to these waters. Join National Geographic for a glimpse into this growing problem and learn about working solutions.

Massive volcanic eruptions can turn day into night, releasing the power of an atomic blast, spewing toxic avalanches of lava, gas, and ash. National Geographic transports you to some of the world's most notorious volcanoes, including Mount Pinatubo in the Philippines and Japan's Mount Unzen. Join volcanologists in their dangerous quest to forecast eruptions and save lives, putting you in the middle of the explosive excitement and human drama.

The globe learned on Dec. 26, that tsunamis can bring death and devastation to the world's coastlines. The product of undersea earthquakes and volcanic eruptions, tsunamis can race across oceans at more than 500 miles an hour, leaving a huge wake of destruction when they hit shore. Because it is difficult for scientists to predict how large these massive waves can be, tsunamis are one of the least understood of nature's forces, and one of the most dangerous. With insight from some of the scientific community's foremost researchers, and vivid accounts from past tsunami survivors, National Geographic's ''Tsunami: Killer Wave'' depicts nature at its most extreme, profiles the efforts being made to curb its effects and illustrates the financial, physical and emotional toll it can leave on its victims.

National Geographic presents a story of competing interests, commerce, and conservation, arrogance and awe. It documents our temporary triumphs over nature, and shows how some solutions result in new problems. Above all, it’s a call to action for everyone.

In the frozen wilderness of Antarctica, where oceans ice over and just staying alive is an achievement, one creature has perfected the art of survival - the emperor penguin. Emperor penguins are sublimely built to conquer the cold – but in a world threatened by climate change, can they take the heat? Parts of Antarctica are warming, giving birth to huge icebergs, and the consequences could be catastrophic in a place where all life is touched by the ice. Using Crittercam, scientists hitch a virtual ride under the ice with the emperor penguin to study the impact of climate change on the penguin’s world.

Where and when the next mega disaster will strike —volcanic eruption, earthquake, tsunami or hurricane—is the focus of Violent Earth. Join tsunami scientist Jose Borrero of the University of Southern California on his trip to visit Banda Aceh with a National Geographic film team, barely one week after the December 26, 2004, tsunami—a tsunami so strong it actually moved the island of Sumatra a hundred feet.

In the great wild heart of South America there are few roads or cities. A vast expanse of pristine wilderness lies here, dominated by water and spread out under a storm filled sky. It is an awe-inspiring landscape, magnificent in its grandeur. However, for the creatures that live here, this is no paradise; they are subject to the extremes of the seasons and the edicts of nature’s law. Within these shimmering waters lurks danger - legendary monsters and beasts whose ferocity and appetites are notorious… From the Amazon basin down to Argentina, much of South America’s rivers are inhabited by piranha. Most are harmless, but a handful are not. These are the notorious red piranha – they have been called the most ferocious fish in the world. But just how dangerous are they?

Few creatures are as mysterious and captivating as the whale. Embark on a globe-spanning journey with National Geographic to discover the most recent findings about these majestic, highly intelligent creatures. After hunting whales for generations, we have brought their widespread slaughter to an end, but these graceful giants still face threats on a number of fronts and the battle to save them goes on. It’s a gripping, sometimes emotional voyage to the front lines of research as a new breed of champions’ battles to understand and preserve these spectacular giants of the sea.