Seven Worlds, One Planet

Australia, a land cast adrift at the time of the dinosaurs. Isolated for millions of years, the weird and wonderful animals marooned here are like nowhere else on Earth. In the north of this island continent is the Daintree, one of the world's oldest tropical forests. It's home to the most dangerous bird on earth - the cassowary. A dinosaur-like bird standing six feet tall. On the open grasslands the dingo, Australia'€s elusive and much persecuted wild dog, hunts kangaroos to provide food for its pups. Chases can cover many miles and are often unsuccessful. Life in Australia is tough and getting tougher. Over 70% of Australia is now arid land.

More than any other continent, North America is defined by extreme weather and seasonal change. For animals that live here this poses great challenges, but for those with a pioneering spirit it can also offer great rewards.

South America is the most species rich continent on Earth. From the bone-dry deserts of the Atacama, where penguins weave their way through a minefield of snapping sea lions, to the lush cloud forests of the Andes, where Andean bears scale 30-meter trees in search of elusive fruits, South America is full of the unusual and ingenious.

Asia is the largest and most extreme continent on our planet, stretching from the Arctic Circle to the tropical forests on the equator. The animals here face the hottest deserts, tallest jungles and highest mountains found anywhere on Earth. In the frozen lands of the Kamchatka peninsula in Russia, bears seek out active volcanoes - despite the dangers. And on the Siberian coast, a remarkable spectacle appears for a few weeks during the summer - tens of thousands of walruses haul themselves onto a beach in one of the largest gatherings of mammals seen anywhere in the world.

Europe is a crowded continent transformed by mankind where extraordinary animals are found in surprising places. High above the city of Gibraltar, Barbary macaques - Europe's only non-human primates - live lives full of kidnappings and high drama, while in the cemeteries of Vienna 'grave robbing' European hamsters battle each other for food. Come nightfall, the forests surrounding ancient Italian mountain villages become the hunting grounds for rarely seen wolves, and deep underground in Slovenia's caves, olms or 'baby dragons' can be found lurking in the pitch black.

Antarctica is a land of survivors enduring the most hostile conditions on Earth. 98% of the mainland is covered by ice on which virtually nothing can live. Even the sea freezes over, but the Weddell seal manages to survive. Below the sea ice, conditions have been stable for millennia and life has flourished and diversified. Starfish, sea spiders and three million predatory worms carpet the ocean floor, and sea anemones feast on ocean giants. Islands on the fringes of the continent, free of sea ice, are far more crowded. Huge colonies of king penguins cover the land, and four-ton elephant seals fight for territories on the beach. The abundance of life found here is due to the incredibly rich ocean surrounding the continent.

Africa is home to the greatest wildlife gatherings on Earth. But even in this land of plenty, wildlife faces huge challenges. At its heart is a vast tropical rainforest full of life. Here young chimpanzees learn how to use tools to make the most of the jungles riches. Rivalling the jungle for its sheer abundance of life is Africa's Great Rift Valley, the richest freshwater habitat on the planet. Africa's rich Serengeti grasslands are home to the greatest herds of antelopes, wildebeest and zebras. Close behind them are their predators.