Realm of the Alligator

An examination of the extinction threat faced by frogs, which have hopped on Earth for some 250 million years and are a crucial cog in the ecosystem. Scientists believe they've pinpointed a cause for the loss of many of the amphibians: the chytrid fungus, which flourishes in high altitudes. Unfortunately, they don't know how to combat it. Included: an isolated forest in Panama that has yet to be touched by the fungus, thus enabling frogs to live and thrive as they have for eons.

Documentary series uncovering the secret lives of big cats, using the latest technology and scientific research to bring these animal superstars out of the shadows.

A group of scientists are thinking outside the box for ways to reverse the effects of global warming. And who better to save the earth than National Geographic Channel's host of the World's Toughest Fixes, Sean Riley? He'll join these experts in the labs and in the field to see what wacky new technologies are being developed, like sending mirrors into space and reducing the greenhouse emissions chickens produce.

In 2009 a team of British cavers went on an expedition deep within the jungle of central Vietnam. To their amazement they discovered an enormous cave which they believe to be the biggest in the world. The team, the first humans ever to enter the cave, traveled 6 kilometers underground until their way was blocked by a gigantic rock face they dubbed 'The Great Wall of Vietnam'. Now they have returned, but this time with the right equipment to climb the wall and with a geologist and zoologist to discover if this is indeed the Biggest Cave in the World and what secrets lie deep within?

Embark to Niagara Falls and witness its stunning beauty and a wide variety of wildlife—mammals, birds, and reptiles. Through the eyes of passionate scientists, uncover a complex world forged by stone and powered by water.

Every year, thousands of Antarctica's emperor penguins make an astonishing journey to breed their young. They walk, marching day and night in single file 70 miles into the darkest, driest and coldest continent on Earth. This amazing, true-life tale is touched with humour and alive with thrills. Breathtaking photography captures the transcendent beauty and staggering drama of devoted parent penguins who, in the fierce polar winter, take turns guarding their egg and trekking to the ocean in search of food. Predators hunt them, storms lash them. But the safety of their adorable chicks makes it all worthwhile. So follow the leader... to adventure!!

Snakes, creatures with superpowers that have allowed them to adapt perfectly to their environment, play an essential role in the ecosystem.

The Amazon is one of the wildest and least explored parts of the planet. Encompassing 6 countries and 2 million square miles of forest, river and floodplain, it has the highest diversity of life on the planet, but what lies below it is truly shocking. In its deep muddy rivers, clear streams and expansive floodplains a freak-show of fish life has exploded, with some of the strangest shapes and weirdest adaptations on Earth. Hiding in the vast rivers and streams is an electric grid, a bizarre community of fish with a highly sophisticated electric sixth sense. Using electricity, these "Super" fish can communicate wirelessly, control each other remotely and emit shocks that can stop a human heart. This cryptic world has mystified scientists throughout the ages. Now an intrepid scientist, Will Crampton ventures back into the dark jungles where the inspiration for our technology driven world first emerged, in an attempt to unravel their secrets and unlock the electric code.

Climate change has reached the indigenous Nenets people in the north of Siberia. The nomads' herds of reindeer move on thin ice. The warming in the Russian Arctic is becoming dramatically visible. Huge craters open in the thawing permafrost and expose dangerous viruses and bacteria. Forest floors dry out and the taiga catches on fire. The pack ice off the coast is melting and depriving polar bears of their habitat so that they approach human settlements in their desperation. The changes in the nature of the Arctic Circle combine with the measurements of researchers and observations of the indigenous people to form a disturbing overall picture: In the Russian Arctic, Pandora's box has been opened! The film team had the chance to shoot in regions that were been restricted areas for decades. The documentary shows in impressive and depressing images already existing effects, phenomena and ominous interlinkages of global warming.

A look at the state of the global environment including visionary and practical solutions for restoring the planet's ecosystems. Featuring ongoing dialogues of experts from all over the world, including former Soviet Prime Minister Mikhail Gorbachev, renowned scientist Stephen Hawking, former head of the CIA R. James Woolse